A vertically movable workpiece support device has a ratchet wheel with a larger diameter than the outer diameter of a driving sprocket wheel and is concentrically attached to an end surface of a boss portion in the driving sprocket wheel. A pair of left and right bearing members are provided side by side, on a side on which the free end side of a drive chain is horizontally extended with respect to the driving sprocket wheel, so as to sandwich a horizontally extending path section of the drive chain. A movable pawl is pivotally supported between the pair of left and right bearing members and engages with the ratchet wheel to block the rotation of the ratchet wheel caused by the movement of the drive chain when the workpiece support base is lowered. An actuator switches the movable pawl to a non-action position with respect to the ratchet wheel.

A vertically movable workpiece support device has a ratchet wheel with a larger diameter than the outer diameter of a driving sprocket wheel and is concentrically attached to an end surface of a boss portion in the driving sprocket wheel. A pair of left and right bearing members are provided side by side, on a side on which the free end side of a drive chain is horizontally extended with respect to the driving sprocket wheel, so as to sandwich a horizontally extending path section of the drive chain. A movable pawl is pivotally supported between the pair of left and right bearing members and engages with the ratchet wheel to block the rotation of the ratchet wheel caused by the movement of the drive chain when the workpiece support base is lowered. An actuator switches the movable pawl to a non-action position with respect to the ratchet wheel.

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. Further, the scissors lift comprises a motor providing said actuation force, said motor located between said opposite scissors arm surfaces of said central hollow scissors arm. Thereby, the motor may be protected and at least partially enclosed by the scissors lift and even by the central hollow scissors arm, allowing a safer and/or more easily maintained scissors lift.

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. Further, the scissors lift comprises a motor providing said actuation force, said motor located between said opposite scissors arm surfaces of said central hollow scissors arm. Thereby, the motor may be protected and at least partially enclosed by the scissors lift and even by the central hollow scissors arm, allowing a safer and/or more easily maintained scissors lift.

An extendable arm includes first and second rigid members forming a cross unit. Each rigid member includes one end portion including one of end coupling shafts, the other end portion including the other end coupling shaft, and a middle portion including a middle coupling shaft. The one end portion of each rigid member includes a bottom-side outer side surface that surface-contacts a base surface when the extendable arm in an extended state is placed thereon. The other end portion of each rigid member includes a top-side outer side surface extending parallel to the bottom-side outer side surface of each rigid member. The middle portion of each rigid member includes a middle strip region passing through a middle coupling shaft and perpendicular to the bottom-side outer side surface and the top-side outer side surface.

An extendable arm includes first and second rigid members forming a cross unit. Each rigid member includes one end portion including one of end coupling shafts, the other end portion including the other end coupling shaft, and a middle portion including a middle coupling shaft. The one end portion of each rigid member includes a bottom-side outer side surface that surface-contacts a base surface when the extendable arm in an extended state is placed thereon. The other end portion of each rigid member includes a top-side outer side surface extending parallel to the bottom-side outer side surface of each rigid member. The middle portion of each rigid member includes a middle strip region passing through a middle coupling shaft and perpendicular to the bottom-side outer side surface and the top-side outer side surface.

A vertically movable workpiece support device has a drive chain bendable to only one side which supports a workpiece support base in a vertically linear path section. The drive chain extends from one end portion coupled to the workpiece support base to an intermediate portion engaging with a driving sprocket wheel. A chain guide plate which sandwiches, with the driving sprocket wheel, a link-to-link roller of the drive chain is arranged on an outer side of the driving sprocket wheel. A mark is displayed, on the side surface of the chain guide plate, in a position separated a certain distance outward from a turning path of links in the drive chain, and an opening portion for visually checking the mark is provided in a side wall which pivotally supports the driving sprocket wheel.

A vertically movable workpiece support device has a drive chain bendable to only one side which supports a workpiece support base in a vertically linear path section. The drive chain extends from one end portion coupled to the workpiece support base to an intermediate portion engaging with a driving sprocket wheel. A chain guide plate which sandwiches, with the driving sprocket wheel, a link-to-link roller of the drive chain is arranged on an outer side of the driving sprocket wheel. A mark is displayed, on the side surface of the chain guide plate, in a position separated a certain distance outward from a turning path of links in the drive chain, and an opening portion for visually checking the mark is provided in a side wall which pivotally supports the driving sprocket wheel.

A lifting apparatus having two rails spaced apart at a distance and two lifting mechanisms, each lifting mechanism supporting one of the two rails. A platform is disposed between the two rails such that movement of the lifting mechanisms causes the rails to displace relative to the platform. A base has the two lifting mechanisms connected thereto and the platform is connected to the base. The base moves horizontally along a floor. Further, the floor may be disposed in a pit and the travel of the rails between minimum and maximum rail heights may be greater than 62.5% of the depth of the pit. The minimum rail height may be less than 50% of the depth of the pit.

A lifting apparatus having two rails spaced apart at a distance and two lifting mechanisms, each lifting mechanism supporting one of the two rails. A platform is disposed between the two rails such that movement of the lifting mechanisms causes the rails to displace relative to the platform. A base has the two lifting mechanisms connected thereto and the platform is connected to the base. The base moves horizontally along a floor. Further, the floor may be disposed in a pit and the travel of the rails between minimum and maximum rail heights may be greater than 62.5% of the depth of the pit. The minimum rail height may be less than 50% of the depth of the pit.