Abstract: A scissor lift (100) for use in a stage assembly includes a base portion (110) configured to be supported on a floor or other support surface and a top portion (120) configured to support a platform. A scissor arm assembly (130) connects the base portion (110) and the top portion, and a rigid chain lifting system (150) comprising a rigid chain (151) connecting the base portion (110) and the top portion (120). Extension and retraction of the rigid chain (151) causes the top portion (120) to rise and fall with respect to the base portion (110). The use of a rigid chain lifting system (150) means that the scissors (130) are provided for guidance rather than applying load. The scissor lift (100) can be used in conjunction with one or more passive scissors (200), couplable to the scissor lift (100).

Abstract: A stand for supporting a printing device, the stand comprising: a first leg and a second leg, the legs having upper ends for vertically supporting a printing device to horizontally span the legs above a supporting surface; a crossbar fixed to the first leg at a first crossbar fixation point and fixed to the second leg at a second crossbar fixation point; and a linkage connected between the first and the second leg, the linkage comprising a first link, a second link and a third link connected in series, wherein: the first link is connected to the first leg in use at a first leg connection point; the second link is connected to the second leg in use at a second leg connection point; and the third link is connected to the crossbar to pivot about a third linkage pivot point and to the first and second links at first and second linkage connection points on opposite sides of the third linkage pivot point.

Abstract: A lift for elevating an object having a base including two legs, lifting apparatus associated with each leg, vertically telescoping guard elements extending along each leg, the lifting apparatus being arranged to lift an object disposed above a plane between said legs, the guard elements telescoping vertically when the lifting apparatus is deployed to exclude a person's limb from a space above said planes.

Abstract: A television mounting assembly includes a pair of first support brackets each having a lower portion, a central portion angling outwardly from the lower portion and an upper portion extending away from the central portion. Each of the first support brackets is attachable to a vent window frame in a sleeper of a semi-truck and a bed support in the sleeper of the semi-truck. A television mounting bracket is attachable to the upper portion of each of the first support brackets and can be positioned at a variety of locations along the upper portion. A second support bracket is attachable to the central portion of each of the first support brackets such that the second support bracket extends between the first support brackets. A sound bar bracket is mountable to the second support bracket thereby facilitating a sound bar to be mounted to the sound bar bracket.

Abstract: A system for supporting or positioning a patient before, during, or after a medical procedure can include a platform configured to support at least a portion of a patient. A support column can be positioned beneath the platform. A base can be positioned beneath the support column and configured to support the support column. The base can include at least one drive wheel configured to contact a ground surface and move the platform with respect to the ground surface. A drive assist user interface module can be operatively connected to the at least one drive wheel. The drive assist user interface module can be configured to permit an operator of the system to selectively control movement of the at least one drive wheel. The drive assist user interface module can be part of or be attached to an attachment that includes a plate having a top surface.

Abstract: A safety latch system includes a mount, a pawl member, a ratchet member, and a release assembly. The mount is mountable on a housing of a piston. The pawl member is coupled to the mount. The pawl member includes a pawl. The ratchet member has a first sidewall that includes a first connecting portion that is connectable to an end portion of a piston rod of the piston. The first sidewall includes a teeth portion, which is configured to engage with the pawl. The release assembly is configured to provide an engaged state between the pawl member and the ratchet member. The release assembly is also configured to provide a disengaged state between the pawl member and the ratchet member.

Abstract: A lift device includes a base, a platform configured to support an operator, and a scissor assembly coupling the base to the platform. The scissor assembly includes a first scissor layer including a first inner arm pivotally coupled to a first outer arm. The first inner arm is configured rotate relative to the first outer arm about a first middle axis. The first scissor layer has a first end axis center point. An actuator is configured to move the platform between a fully raised position and a fully lowered position relative to the base. The first middle axis is offset vertically from the first end axis center point.

Abstract: A linkage assembly including first, second, third, fourth and fifth elongate linkage members 12, 14, 16, 18 and 20 respectively, a first connecting arrangement 22 for connecting and allowing pivotal displacement between proximal end regions of the first and second elongate linkage members 12 and 14 respectively, a second connecting arrangement 24 for connecting and allowing pivotal displacement between distal end regions of the first and third elongate linkage members 12 and 16 respectively, a step support connecting arrangement 26 for connecting the first and fourth elongate linkage members 12 and 18 respectively, the step support connecting arrangement 26 being located inwardly the second connecting arrangement 24 and provides a stepping formation 30 for a user, the step support connecting arrangement 26 including a shaft 32 having a first portion 34 which is shaped to be received by and inhibit relative pivotal displacement between the fourth linkage member 18 and the stepping formation 30 during extension

Abstract: An expandable car jack includes a vehicle lifting assembly with an upper lifting member, a lower lifting member mechanically coupled to the upper lifting member, and a lifting mechanism capable of moving the upper lifting member to a plurality of raised height positions. A base is coupled to the vehicle lifting assembly and includes a first base support member, a second base support member, and a base support coupler that is operable to selectively couple the first base support member to the second base support member in at least a first coupling position and a second coupling position.

Abstract: A desktop workspace that adjusts vertically includes a work surface platform, a base configured to sit on an existing platform, such as a desk, a height adjustable mechanism including at least one set of arms that connect at a pivot point(s) creating a scissoring motion to raise and lower the said work surface platform to various heights. A locking and unlocking mechanism may connect to the height adjustable mechanism. In some cases, the apparatus includes an adjustable mechanism to support items such as a keyboard. In some cases, the apparatus includes elements to raise items such as a monitor to an additional height.

Abstract: A lift raises and lowers a boat to load and unload the boat onto a roof of or a roof rack on a vehicle. The lift has an upper frame having a longitudinal axis, a lower frame having a longitudinal axis, and a linkage connecting the upper frame to the lower frame. In a first position the linkage is extended and the lift is raised and in a second position the linkage is retracted and the lift is lowered. At least one lift rack extends from or is part of the upper frame. The lift rack is adapted to support a boat at least vertically such that in the extended linkage first position a boat may be slid in a longitudinal direction between the lift rack and the roof or the roof rack of the vehicle. A method for using the lift is also disclosed.

Abstract: A desk-mounted lifting platform with a workbench, an upper support and a low support, is disclosed. The workbench is connected to the upper support. A first lifting arm and a second lifting arm are arranged between the upper support and the lower support. The first lifting arm and the second lifting arm are X-shaped and hinged at an intersection thereof. An upper end of the first lifting arm is hinged with the upper support. A lower end of the first lifting arm is slidably fitted on the lower support. A lower end of the second lifting arm is hinged with the lower support. An upper end of the second lifting arm is slidably fitted on the upper support. A gas spring is arranged between the upper support and the lower support.

Abstract: The wheel lift for changing tire on a vehicle (hereinafter wheel lift) is a mechanical structure. The wheel lift forms a jack used to elevate a vehicle such that the wheel of the vehicle can be removed and replaced. The wheel lift is a portable structure. The wheel lift is a rolling structure. The wheel lift is a non-Euclidean structure such that the wheel targeted for replacement can roll onto the wheel lift. The wheel lift comprises a pedestal, a jack structure, and a wheel rack. The jack structure attaches the wheel rack to the pedestal. The span of the length of the jack structure in the vertical direction adjusts such that the jack structure controls the elevation of the wheel rack above the supporting surface. The wheel rack receives and supports the wheel targeted for replacement.

Abstract: A tonneau cover system for a vehicle includes a cover, a scissor lift assembly, and an electric actuator. The scissor lift has a fixed arm for mounting to an inner side panel of a cargo bed of the vehicle and a plurality of movable arms coupled to the fixed arm for selectively raising and lowering the cover in dependence upon a distance between a drive point on one of the movable arms and the fixed arm. The electric actuator has an end anchored at a fixed position relative to the fixed arm and a second end coupled to the drive point. The actuator dynamically changes length under electrical power to be between an extended length and a retracted length thereby changing the distance between the drive point and the fixed arm. A controller control the electric actuator to change length in accordance with a user input signal.

Abstract: A system for adjusting surface level, comprising a moveable surface; a mechanism adapted to be disposed between and coupled to the moveable surface and a fixed surface; a force transfer mechanism configured to be coupled to the mechanism for displacement of the moveable surface relative to the fixed surface; and a plurality of stopping rods, disposed between the moveable surface and the fixed surface, which are operative for restricting an axial movement of the moveable surface relative to the fixed surface in a first mode of operation and for restricting a radial movement of the moveable surface relative to the fixed surface in a second mode of operation.

Abstract: An apparatus for plumbing a transmission or distribution pole comprising: multiple pole brackets connected with an adjustable ratchet strap; multiple scissor jacks with each having a jack mount; at least one power drill or hand crank to adjust the scissor jack; whereby the pole can be efficiently adjusted into the proper plumb or leveled position.

Abstract: A patient support apparatus includes a frame supported relative to a floor, the frame configured to support a deck for supporting a patient thereon, and a lift assembly for raising or lowering the frame relative to the floor. The lift assembly includes lifting legs coupled to the frame and an actuator with a body and an extendible member. The body and the extendible member define a stroke length extending along a stroke axis, with the actuator mounted in the lifting assembly between two levers.

Abstract: A system for adjusting surface level, including a moveable surface, at least two structures adapted to be disposed between and coupled to the moveable surface and a fixed surface, a single force transfer mechanism configured to be coupled to the at least one of the at least two structures for displacement of the moveable surface relative to the fixed surface.

Abstract: An elevation working platform includes a lower support and an upper support. At least one group of X-type elevation mechanisms is provided between the lower support and the upper support. The elevation working platform further includes an elastic element. A first end of the elastic element is connected between two end points of a first support rod or a second support rod. A second end of the elastic element is connected to the lower support or a second hinging seat capable of sliding relative to the lower support. Using the X-type elevation mechanisms, the front and back positions of the upper support do not change in an elevating process of the upper support, the structure is simple and practical, and the cost is relatively low.

Abstract: A scissor jack kit to elevate each vehicle quadrant for maintenance including one scissor jack for each wheel. Each scissor jack includes a parallelepiped bottom base, a lower support base atop thereof, and mirror image first and second arms, each having top and bottom ends hinged at a central elbow. Each of proximal and distal ends of the bottom and top ends, respectively, pivotably couples to the respective lower and upper support base. An aperture in the central elbow receives a rotatable leadscrew therethrough having a socket with a hole which receives a hook of a jack speed crank handle to rotate the leadscrew to adjust the scissor jack height. Mount holes in the upper support base provide for chassis mounting. A groove in an axle mount body on the upper support base supports the axle proximal the respective wheel and has a cushioned lining thereon.

Abstract: The present invention relates to a scissors lift comprising a bottom frame, a top frame and a scissors mechanism arranged between the bottom frame and the top frame to displace the bottom frame and the top frame relative to each other by transfer of an actuation force. The scissors mechanism comprises a central hollow scissors arm delimited between opposite scissors arm surfaces, wherein the central hollow scissors arm has a bottom pivotal connection connecting it to the bottom frame and a top pivotal connection connecting it to the top frame. Further, the mechanism comprises two passive scissors arms being pivotally connected to the bottom frame and pivotally connected to the top frame. Each of the two passive scissors arms are pivotally connected to the central hollow scissors arm on the opposite scissors arm surfaces of the central hollow scissors arm.

Abstract: A vehicle leveling system includes a jack adapted to be mounted to a vehicle frame without modifying the vehicle frame. In a particular embodiment, the jack includes a first bracket adapted to urge against the bottom surface of the frame and a second bracket adapted to be mounted to a surface of the vehicle adjacent the frame. In a more particular embodiment, the first bracket includes a horizontal adjustment feature and the second bracket includes a vertical adjustment feature. In another particular embodiment, the jack is coupled to the vehicle frame via a bracket that is adapted to be mounted to manufacturer-provided apertures formed in the frame during the manufacture of the vehicle.

Abstract: A parking lift for vehicles. The parking lift includes a platform on which a vehicle can be parked and lifted by a pair of scissor-lifts configured to raise and lower the platform to enable parking of a second vehicle beneath the platform. A deck of the platform is provided with a gradual slope throughout its length to enable vehicles with low ground clearance to travel onto the platform without contacting an underside of the vehicle with the deck. The scissor-lifts each include a leg with a recessed portion that increases a spacing between a door of a vehicle parked under the platform and the leg and thus a range of motion available to the door. A pad may be disposed on the leg in the recessed portion to protect the door against damage caused by contacting the leg.

Abstract: A device for compensating for the natural shrinkage of building materials includes one or more gear members mounted on a base plate. A fastener extends through a hole in the base plate and axially fixed relative to the gear member. The gear member is engaged with teeth in the base plate and rotatable relative to the fastener. The axis of rotation of the gear member is not aligned with its central axis. The base plate can be securely fastened to a first building member with the fastener axially fixed relative to a second building member but not axially fixed relative to the base plate and first building member.

Abstract: A robot including a base having a flat mounting surface section to be set on an installation surface by a fixing part, and also including a movable unit that is movable relative to the base. The base includes a tip-over prevention member that is disposed in a switchable manner between a state where the tip-over prevention member at least protrudes forward from the mounting surface section in a moving direction when a relocating process is performed and a state where the tip-over prevention member does not protrude forward from the mounting surface section.

Abstract: A lift and tilt support apparatus includes opposed scissor lift assemblies. Each scissor lift assembly includes a base, an upper frame, and scissored first and second legs, each having opposed top and bottom ends. The bottom end of the first leg is pivoted to the base, and the top end of the first leg is mounted to the upper frame for reciprocal movement. The top end of the second leg is pivoted to the upper frame, and the bottom end of the second leg is mounted to the base for reciprocal movement. The top end of the first leg reciprocates in a direction skewed from the top end of the second leg. The bottom end of the second leg reciprocates in a direction skewed from the bottom end of the first leg.

Abstract: A lid assembly for a truck bed with two opposite vertical side walls includes a lid adapted for covering the truck bed, the lid being movable in a first direction between an open and closed position, two scissor hinges adapted for mounting the lid to the truck bed, each of the two scissor hinges having a first hinge member adapted for being slidably and pivotably connected to a respective side wall of the truck bed at a first end and being pivotably connected to the lid at a second end, and a second hinge member which is slidably and pivotably connected to the lid at a first end and adapted for being pivotably connected to the respective side wall at a second end. The assembly further includes an opening element adapted for, upon actuation, applying a force to at least one of the first ends of the hinge members in a second direction, which extends in an angle of between 85 and 90 degrees with respect to the first direction, to move the lid in the first direction.

Abstract: An operation device includes a main body, a lifting and lowering mechanism unit movably supported with respect to the main body and including a driven portion configured to receive driving force for movement of the lifting and lowering mechanism unit, a driving unit attached to the main body and configured to drive the lifting and lowering mechanism unit by a driving pin provided on a rotation gear. The lifting and lowering mechanism unit includes a groove portion into which the driving pin is accommodated by rotation of the rotation gear when the driving unit is mounted on the main body.

Abstract: A workpiece lifting and lowering device is provided with: a workpiece base supported as to be capable of being lifted and lowered, and mounting a workpiece; a link mechanism connected to the workpiece base, and lifting and lowering the workpiece base by converting a rotation motion to a lifting and lowering motion; and a driving mechanism rotationally driving the link mechanism through a transmission member.

Abstract: A high visibility push-pull handler configured to be mounted on a lift truck. The handler comprising a frame assembly, a pantograph mechanism coupled to the frame assembly, and a faceplate assembly coupled to the pantograph mechanism. The hander is configured with a view window extending through the handler, the view window not obstructed by parts of the handler when the handler is in any normal operating configuration, including a fully extended configuration, a fully retracted configuration, and any configuration in between the full extended and fully retracted positions.

Abstract: A desktop workspace that adjusts vertically includes a work surface platform, a base configured to sit on an existing platform, such as a desk, a height adjustable mechanism including at least one set of arms that connect at a pivot point(s) creating a scissoring motion to raise and lower the said work surface platform to various heights. A locking and unlocking mechanism may connect to the height adjustable mechanism. In some cases, the apparatus includes an adjustable mechanism to support items such as a keyboard. In some cases, the apparatus includes elements to raise items such as a monitor to an additional height.

Abstract: A desktop workspace that adjusts vertically includes a work surface platform, a base configured to sit on an existing platform, such as a desk, a height adjustable mechanism including at least one set of arms that connect at a pivot point(s) creating a scissoring motion to raise and lower the said work surface platform to various heights. A locking and unlocking mechanism may connect to the height adjustable mechanism. In some cases, the apparatus includes an adjustable mechanism to support items such as a keyboard. In some cases, the apparatus includes elements to raise items such as a monitor to an additional height.

Abstract: An elevation working platform includes a lower support and an upper support. At least one group of X-type elevation mechanisms is provided between the lower support and the upper support. The elevation working platform further includes an elastic element. A first end of the elastic element is connected between two end points of a first support rod or a second support rod. A second end of the elastic element is connected to the lower support or a second hinging seat capable of sliding relative to the lower support. Using the X-type elevation mechanisms, the front and back positions of the upper support do not change in an elevating process of the upper support, the structure is simple and practical, and the cost is relatively low.

Abstract: A mobile storage device is disclosed. The mobile storage device comprises a frame, an extension device, a storage bin, and a control system. The extension device is rotatably connected to the frame. The storage bin is secured to the extension device. The control system is rotatably connected to the frame.

Abstract: A push-to-connect fitting removal tool that includes first and second handles pivotally-connected for being grasped and manually moved towards and away from each other, a first guide bar connected to both the first and second handles, and a second guide bar connected to both the first and second handles and cooperating with the first guide bar for converting pivotal movement of the first and second handles into non-pivoting, translation motion of the first and second guide bars. A push fitting jaw is attached to the first guide bar and a pipe jaw is attached to the second guide bar for being moved towards and away from each other as the first and second handles are moved towards and away from each other. The push fitting jaw is adapted for at least partially encircling the push fitting and the pipe jaw adapted for at least partially encircling the pipe.

Abstract: A rise prevention device for a vehicle body and a vehicle assembly system including the same are provided. The a rise prevention device for a vehicle body includes an elevation device that is configured to move up and down and a power base that is configured to move up and down on the elevation device. In addition, a pressing device is configured to move up and down, is supported by the power base and is configured to press against the vehicle body to prevent the vehicle body from rising.

Abstract: A lifting and supporting table according to the present invention includes an upper platform having a receiving surface and a lower frame supporting the upper platform. The lifting and supporting table includes a linkage interacting with the lower frame such that adjustment of the linkage forces a height of the upper platform to change. A ramp assembly includes a ramp having a top surface that operatively extends the receiving surface of the upper platform, the ramp being selectively moveable between a horizontal position and an inclined position.

Abstract: A radial-scissor lift assembly for a table top comprising an upper support member, a lower support member, and at least three scissor assemblies coupled to the upper and lower support members. Each scissor assembly includes a table-scissor member rotatably supporting a table wheel adapted for contacting an unattached table. Each scissor assembly further includes a floor-scissor member rotatably supporting a floor wheel adapted for contacting a surface supporting the radial-scissor lift assembly. The radial-scissor lift assembly has an actuator assembly coupled to the lower support member and to the upper support member for moving the scissor assemblies. A method for lowering a table top comprising disposing a table top on at least three table rollers, and rolling the table rollers along the bottom on the table top and away from the center of the table top to cause the table top to be lowered.

Abstract: A lifter is provided with operating levers, which, against driving forces of actuators that switch the ratchet pawls to unengaged orientations, switch the ratchet pawls to engaged orientations of being engaged with ratchet gears, is provided with a link mechanism, which, when a workpiece support base is being lowered by collapsing motions of a pair of right and left crosslink mechanisms supporting the workpiece support base and a difference arises in movement amounts of movable support shafts at lower end sides of the respective crosslink mechanisms, converts the movement amount difference to an operating force of the operating lever at the larger movement amount side, and is such that by the operating lever at one side being driven by the link mechanism, the operating lever switches the ratchet pawl at the larger movement amount side to the engaged orientation.

Abstract: A manual vehicle ramp jack with an auxiliary hydraulic jack including a pair of parallel tire ramps and a lifter base disposed on the front end of each tire ramp, which has a riser plate movably disposed within a central aperture thereof from a lowered, recessed condition to an alternate raised condition. Each riser plate is provided to receive a tire therein. A manually operated mechanical foot jack is in operational communication and a mechanical hydraulic toe jack is in alternate operational communication with the riser plate of each lifter base. A foot-depressible crossbeam operationally connects the foot jacks together which permits the foot jacks to be operated simultaneously.

Abstract: A scissor lift table (1) has a first base element (2) and a second base element (3) and a scissor (4). The scissor (4) has a first scissor part (6) and a second scissor part (7), wherein the first scissor part (6) and the second scissor part (7) are pivotable relative to one another about a scissor axis (5). The first base element (2) and the second base element (3) are connected by the scissor (4) such that a pivoting of the scissor parts (6, 7) relative to one another about the scissor axis (5) causes a change in the distance between the first base element (2) and the second base element (3), wherein the first scissor part (6) is pivotably borne on the first base element (2) using a fixed bearing (10) and the second scissor part (7) is displaceably and pivotably borne on the first base element (2) using a floating bearing (11).

Abstract: A mud flap retraction assembly that allows actuating a vehicle's rear mud flaps between lower and upper positions.

Abstract: A scissor lift apparatus includes a sliding carriage member and a pivoting linkage added to a conventional scissor lift in order to lower the force required to lift a tray holding heavy media during the initial portion of the lifting action where the scissor lift is fully compressed.

Abstract: A preferred embodiment of a system includes a lifting device for lifting a motor vehicle, a support structure for mounting the lifting device in a pit, and a carriage for supporting the lifting device from the support structure and being movable within the support structure. The system also includes a cover coupled to opposite sides of the carriage so that the cover extends away from the carriage and continuously between the opposite sides of the carriage.

Abstract: A conveyance cart that can convey a loaded burden, includes: a body frame supported by a wheel; a deck provided liftably against the body frame to load a burden; an electric actuator electrically driven to expand or contract to lift or lower the deck; and a controller that is configured to supply an electric current to the electric actuator. The controller stops supply of an electric current to the electric actuator when a continuous driving time of the electric actuator is equal to or longer than a predetermined time.

Abstract: A refrigerator is provided including a refrigerator compartment having a bin door. A storage bin is positioned within the refrigerator compartment. A lift mechanism is positioned within the refrigerator compartment. The lift mechanism includes a bin support structure configured to support the storage bin. The lift mechanism further includes at least one pivot arm pivotally attached to the bin door, and a drive unit attached to the bin door. The drive unit applies a vertical force to the at least one pivot arm, and rotation of the at least one pivot arm vertically moves the bin support structure and storage bin.

Abstract: A low-profile mount for a flat panel electronic display that is selectively shiftable between a wall-confronting position wherein the back of the flat panel electronic display is disposed parallel and proximate to the wall surface and a tilt position wherein the top of the display is tilted away from the wall surface. The mount is configured so that points spaced apart forwardly from display receiving surfaces of the mount are shifted along a substantially horizontal axis as the mount is shifted between the wall confronting position and the tilt position. Advantageously, the display can be attached to the mount so that the points are horizontally registered with a center of gravity of the display such that the display is self-balancing at any point along the travel between the wall confronting position and the tilt position.

Abstract: A massage device (10) includes a table top assembly (12) that supports a user above a surface (18). The massage device (10) comprises a leg assembly (14) and an adjuster assembly (16). The leg assembly (14) extends between the table top assembly (12) and the surface (18). Additionally, the leg assembly (14) includes a first leg (24), a second leg (26), and a leg attacher (28) that pivotally secures the first leg (24) to the second leg (26). The adjuster assembly (16) adjusts the position of the table top assembly (12) relative to the surface (18) between a lower position and an upper position. The adjuster assembly (16) includes an adjuster (44) that acts primarily in push mode to pivot the second leg (26) relative to the first leg (24) so that the table top assembly (12) moves between the lower position and the upper position.

Abstract: The subject invention includes a lift system including a first scissor-type lift assembly and a second scissor-type lift assembly spaced from the first scissor-type lift assembly. The first scissor-type lift assembly includes a first base and a first platform coupled to the first base for movement between elevated and lowered states. The first scissor-type lift assembly includes a first motor operatively mounted to the first base. The second scissor-type lift assembly includes a second base and a second platform coupled to the second base for movement between elevated and lowered states. The second scissor-type lift assembly includes a second motor operatively mounted to the second base. The first and second motors move the first and second platforms between the elevated and lowered states. The lift system includes a controller in communication with the first and second scissor-type lift assemblies to synchronize operation of the first and second motors.

Abstract: A jack, defining a portable accessory for replacing a motor vehicle wheel, is adapted to be placed on the ground and has a scissors-like pantograph provided with a first and a second arm hinged to each other; the first and second arms have respective lower end portions, which can be moved close or away by actuating a screw/nut-screw device; the second arm is shorter than said first arm and is provided with an upper end portion hinged to an intermediate portion of the first arm; the jack further has a supporting member, which is supported only by an upper end of the first arm and can rotate about an axis.