Leg device

A leg device includes a leg shaft with a male thread section having a contact section at a lower end thereof, and an elevating part supported on the leg shaft to be capable of rising and lowering. The elevating part includes a base section having a portion to be fixed to an object, a through hole for inserting the leg shaft, and a locking piece integrated with the base section at one end thereof. The locking piece has a female threaded section on a front surface of the other end thereof for engaging the male threaded section of the leg shaft, and an operation knob on a rear surface of the other end. The base section and locking piece are integrally formed to position the female threaded section of the locking piece inwardly beyond an outer surface of the leg shaft passing through the through hole.

BACKGROUND OF THE INVENTION AND RELATED ART STATEMENT

The present invention relates to a leg device to be attached to an object as a leg of the object for adjusting a height of the object.

Japanese Patent Publications (Kokai) No. 11-82881 and No. 2003-311092 disclose height adjustable devices for supporting an object. The devices include a bolt-shaped leg with a ground contact section at a lower end thereof and a member having a nut for engaging a male thread section of the leg, so that the device adjusts a height of the object with the leg.

In the devices, it is necessary to provide at least four components: a case to be fastened to the object, a member disposed in the case as a nut, a spring for urging the member, and the leg as described above.

An object of the present invention is to provide a leg device with a minimal number of components.

SUMMARY OF THE INVENTION

In order to attain the objects described above, according to the present invention, a leg device supports an object to adjust a height thereof. The leg device comprises a leg shaft with a male thread section having a ground contact section at a lower end thereof and an elevating part supported on the leg shaft to be capable of rising and lowering. The elevating part includes a base section having a portion to be fixed to the object, a through hole for inserting the leg shaft, and a locking piece integrated with the base section at one end thereof. The locking piece has a female threaded section on a front face of the other end thereof for engaging the male threaded section of the leg shaft, and an operation knob on a rear face of the other end. The base section and locking piece are integrally formed by plastic molding so as to position the female threaded section of the locking piece inwardly beyond an outer surface of the leg shaft passing through the through hole.

In the present invention, the leg device for supporting an object is appropriately constructed with two parts, i.e., the leg shaft and the elevating part. When the leg shaft is inserted into the through hole of the elevating part while flexibly deforming the locking piece, the female threaded section of the locking piece is pressed against and engages the male threaded section of the inserted leg shaft with a force of the locking piece to restore an original shape. When the leg device is attached to an object via the fastening portion of the base section, it is possible to change a distance between the lower face of the elevating part and the ground contact section of the leg shaft through rotary operation of the leg shaft, thereby enabling fine adjustment of a height of the object.

In the present invention, the elevating part has the female threaded section of the locking piece engaging the male threaded section of the leg shaft. Accordingly, when the leg shaft is rotated, the female threaded section advances or retreats spirally along the leg shaft, thereby gradually adjusting the height of the supported object. Moreover, when the locking piece is deformed to release the female threaded section from the male threaded section of the leg shaft with the operation knob of the locking piece, i.e., the other end of the locking piece is retreated, it is possible to raise or lower the elevating part along the leg shaft, thereby adjusting the height of the supported object.

According to the present invention, the base section may be provided with an upper plate, and one end of the locking piece is integrated with the upper plate of the base section. In this case, when the operation knob is lifted, it is possible to raise or lower the elevating part along the leg shaft, thereby adjusting the height of the supported object. A finger supports the object from underneath and lifts the operation knob without any difficulty.

According to the present invention, the base section may be provided with a side plate having a groove extending horizontally, and the locking piece may be provided with a projection for inserting into the groove. When an object is supported, the female threaded section of the locking piece engages the male threaded section of the leg shaft, thereby applying an upward force to the locking piece. The projection contacts an upper groove wall of the groove to receive the force, thereby preventing damage on the locking piece.

According to the present invention, an elastic engaging piece may be formed at an upper end of the leg shaft. When the leg shaft is inserted into the through hole of the base section of the elevating part, the elastic engaging piece deforms. The elastic engaging piece restores an original shape upon emerging above the through hole to engage the through hole. Accordingly, it is possible to prevent the leg shaft from falling out when the object fastened to the elevating part is lifted.

According to the present invention, the leg device for supporting an object can be appropriately constructed with the two parts, i.e., the leg shaft having the male threaded section and the elevating part having the locking piece, the female threaded section integrated with the base section having the through hole for the leg shaft and the part for fastening the object.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereunder, embodiments of the present invention will be explained with reference to the accompanying drawings.FIGS. 1 to 5show a leg device in use, respectively. In particular,FIG. 5shows a state that an elevating part2is at a lowest position.FIGS. 6 to 11show the elevating part2, respectively.FIGS. 12 and 13show a leg shaft1according to another embodiment of the invention, respectively.

According to the embodiments, the leg device is attached to an object P as a leg, and has a function of supporting the object P to adjust a height thereof (height adjuster function). For example, the leg device may be used as a leg of a projection apparatus such as a liquid crystal projector, a video projector, and a slide projector. The leg device may be attached to a lower end of a tripod as a portion of a leg thereof. When the leg device is used in a projector, the leg device is disposed at a lower front section of the projector where the projection lens is disposed for adjusting an angle of the projector. Accordingly, it is possible to adjust a height of an image projected on a screen.

The leg device includes a leg shaft1and an elevating part2. The leg shaft1is formed of a male threaded section having a ground contact section10at a lower end thereof. The leg shaft1has a disc-shaped section101at the lower end, and the disc-shaped section101includes a cushion material102on a lower surface thereof. The cushion material102contacts a ground surface G, such as a floor, ground, and table surface, to support the object P on the ground surface G.

In the embodiment, unthreaded sections11are provided at both lower and upper ends of the leg shaft1, and a male threaded section12is provided between the unthreaded sections11. The male threaded section12of the leg shaft1engages a female threaded section213of a locking piece21constituting the elevating part2, so that the elevating part2is raised or lowered when the leg shaft1rotates while gripping the disc-shaped section101. The male threaded section12engaging the female threaded section213is not provided at a position where the elevating part2is fully raised or lowered. Accordingly, when the elevating part2is fully raised or lowered, the leg shaft1does not rotate further, thereby preventing damage on the female threaded section213.

In the embodiment, elastic engaging pieces13are formed at an upper end of the leg shaft1. When the leg shaft1is inserted into through holes202of a base section20from underneath, the elastic engaging pieces13deform inwardly, The elastic engaging pieces13then restore an original shape at a location where the elastic engaging pieces13protrude upwardly through the through holes202to engage the through holes202.

In the embodiment, the upper end portion of the leg shaft1is a hollow tube. The elastic engaging pieces13are formed between two grooves14extending in an axial direction of the leg shaft1and having ends opening outwardly at an edge of the upper end portion. The elastic engaging pieces13are formed at both sides of the leg shaft1in a radial direction. One of the elastic engaging pieces13projects upwardly beyond the edge of the upper end portion of the leg shaft1.

A projection131is formed on an outer surface of an upper end of each of the elastic engaging pieces13. The projection131has a catching surface132facing the lower end of the leg shaft1and a slanted surface134. The slanted surface134is formed above a crest133and inclined such that the projection131gradually projects outwardly toward the crest133. A distance between the crests133of the projections131is slightly greater than a diameter of the through holes202of the elevating part2.

When the elevating part2with the leg shaft1is inserted into the through holes202, the slanted surfaces134abut against a rim of the through holes202to smoothly deform the elastic engaging pieces13. The elastic engaging pieces13restore the original shape at the position where they emerge above the through holes202and engage the through holes202. Accordingly, when the object P fastened to the elevating part2is lifted, the leg shaft1does not unexpectedly fall out of the through holes202of the elevating part2.

In the embodiment, one of the elastic engaging pieces13, extends upwardly further than the other of the elastic engaging pieces13. The crests133of the projections131are positioned at different heights. Accordingly, when the leg shaft1is inserted into the through holes202, both of the elastic engaging pieces13do not deform inwardly at the same time, thereby making the insertion easy.

In the embodiment, the leg device is so constructed that the female threaded section213of the locking piece21remains engaging the male threaded section12of the leg shaft1at the position where the catching surface132of the projection131of one of the elastic engaging pieces13(the shorter one) engages the upper opening of the through holes202of the elevating part2. When the elevating part2is raised further by rotating the leg shaft1to position the female threaded section213of the locking piece21at the unthreaded section11, the catching surface132of the projection131of the other of the two elastic engaging pieces13(the longer one) engages the upper opening of the through holes202of the elevating part2. Accordingly, it is possible to prevent the leg shaft1from falling out of the elevating part2at the location where the elevating part2is raised to the full extent.

FIGS. 12 and 13show a structure wherein a plurality of ribs15is formed in a thickness direction of the disc-shaped section101of the leg shaft1with a specific interval in a circumferential direction, thereby making it easy to grip the disc-shaped section101to rotate the leg shaft1. When the elevating part2is lowered, the leg shaft1projects further above the upper surface of the elevating part2. Typically, a housing space Pa is formed at a location where the elevating part2is attached to the supported object P for receiving the leg shaft1passing through the through holes202of the elevating part2and projecting as described above.

The elevating part2is supported on the leg shaft1to rise or lower. The elevating part2integrally includes the base section20and the locking piece21. The base section20includes a fastening portion201to fasten the supported object P, and the through holes202for the leg shaft1. In the embodiment, the base section20is constructed to form a box, with substantially rectangular upper plate203, lower plate204, side plates205disposed between long sides of the upper plate203and lower plate204, and two openings206on both left and right sides. The through holes202for the leg shaft1are formed in the upper plate203and lower plate24at the location near ones of the short sides.

An extension201ais formed to extend laterally from one of the short sides of the upper plate203at the upper section of the base section20. The elevating part2is fastened to the supported object P with a screw S inserted into a hole201bdisposed in the extension201afrom underneath and screwed into the lower surface of the supported object P when superposed on the upper plate203.

One end211of the locking piece21is integrally formed on the base section20. The other end212is provided with a female threaded section213to engage the male threaded section12of the leg shaft1at the front face215thereof, and an operation knob214at the rear face216thereof.

In the embodiment, the locking piece21is a plate formed between the inner faces of the pair of side plates205of the base section20, and has a width to form a gap with each of the inner surfaces. The locking piece21also has a front face215facing the through holes202and the opposing rear face216. The female threaded section213may be formed of a single rib or multiple ribs on the front face215of the end212of the locking piece21td engage the male threaded section of the leg shaft1. In the embodiment, the female threaded section213is formed of a female thread213afor engaging the male threaded section of the leg shaft1, on the front face215of the end212of the locking piece21. An operation knob214extends from the rear face216of the end212of the locking piece21to project an end section thereof outwardly from the opening206of the base section20located near the rear face216.

In the embodiment, the base section20and the locking piece21are integrally formed by plastic molding, so that the female threaded section213of the locking piece21is positioned at a more inwardly penetrated location than the outer surface of the leg shaft1passing through the through holes202. Namely, the locking piece21extends from one side that interposes the axis of the leg shaft1to position the female threaded section213at a location that passes beyond an outer surface position x of the leg shaft1located on the side to approach a y axis of the leg shaft1, or on the y axis, or further enters into the other side that interposes the y axis therebetween.

More specifically, in the embodiment, the base section20and the locking piece21are integrally formed by plastic molding so as to substantially position the female threaded section213of the locking piece21at the location of the y axis of the leg shaft1passing through the aforementioned through holes202.

In particular, the base section20is provided with openings206on the left and right sides. Through the openings206provided on the left and right sides, the locking piece21can be easily and appropriately formed integrally with the base section20within the base section20by plastic molding. As a result, the locking piece21can be flexibly deformed in the direction to retreat the end212including the female threaded section213by using the end211as the center of the deformation. More specifically, the locking piece21can be flexibly deformed by operating the operation knob214that projects from the opening206of the base section20. (The retreated position of the locking piece21is indicated with a dashed line inFIG. 2.)

With the structure described above, the leg device for supporting the object P is appropriately constructed with two parts, i.e., the leg shaft1and the elevating part2. In other words, by allowing the leg shaft1to penetrate into the through holes202of the elevating part2while flexibly deforming the locking piece21, the female threaded section213of the locking piece21is pressed against and engages the male threaded section12of the leg shaft1with the restoration force of the locking piece21. The leg device attached to the supported object P with the fastening portion201of the base section20varies the distance between the lower face of the elevating part2and the ground contact section10of the leg shaft1through the rotary operation of the leg shaft1, thereby enabling fine adjustment of the height of the supported object P.

The elevating part2has the female threaded section213of the locking piece21engaging the male threaded section12of the leg shaft1. Accordingly, the female threaded section213advances or retreats spirally along the leg shaft1relative to the rotation of the leg shaft1, thereby enabling gradual changes in the height of the supported object P. Moreover, the elevating part2can be extensively raised or lowered along the leg shaft1by using the operation knob214of the locking piece21to flexibly deform the locking piece21so as to disengage the female threaded section213from the male threaded section12of the leg shaft1, i.e., by causing the other end of the locking piece21to retreat. Thus, the height of the supported object P can be adjusted extensively.

In the embodiment, the end211of the locking piece21is formed integrally with the upper plate203of the base section20. More specifically, the end211of the locking piece21is integrally connected with the inner face of the upper plate203in the vicinity of the short side opposite to the side where the through holes202is formed in the upper plate203of the base section20. The locking piece21protrudes downwardly in a gradual slant in the direction to penetrate into the base section20from the end211toward the other end212. The end212includes a head section218having the female threaded section213via a neck section217on the front face215, and the operation knob214on the rear face216. The front face215of the head section218, namely, the surface where the female threaded section213is formed, is slanted in the same direction as the slant before the leg shaft1passes through. When the leg shaft1is inserted, the locking piece21is flexibly retreated to the position where the surface is substantially parallel to the axis y of the leg shaft1.

In the embodiment, the elevating part2can be extensively raised or lowered along the leg shaft1by lifting the operation knob214, thereby extensively adjusting the height of the supported object P. The extensive adjustment can be achieved with a finger of a hand that supports the object P from underneath without any difficulty. Laterally extending grooves205aare formed in the side plates205of the base section20; and projections219that penetrate these grooves205aare formed on the sides of the end212of the locking piece21.

In the embodiment, the projections219of the locking piece21are formed on the sides of the locking piece21where the head section218and the neck section217are connected. The projections are disposed on both sides of the locking piece21. The grooves205aare formed on both side plates205of the base section20. The projections219of the locking piece21are formed by plastic molding through the grooves205ain a state that the projections219of the locking piece21are penetrated into the respective grooves205a. Each groove205ahas a main groove section205bformed along a track of the projection219upon the flexible deformation of the locking piece21, and a sub-groove section205cextending upwardly and communicating with a groove edge of the main groove section205bwhere the through holes202are formed.

When the object P is supported, an upward force is applied to the locking piece21with the female threaded section213engaging the male threaded section12of the leg shaft1. The projections219contacts the upper groove walls205dof the grooves205a(the main grooves205a) to receive the force, thereby preventing the locking piece21from damaging.

The disclosure of Japanese Patent Application No. 2004-110964, filed on Apr. 5, 2004, is incorporated in the application.