Vertically adjustable support leg

Abstract

 A vertically adjustable support leg includes an outer shaft (12) with a tapered axial opening (16) and an inner shaft (14) insertable in telescoping fashion into the axial opening. A tapered two-piece sleeve (30) can be mounted about the inner shaft (14) at various heights and secures the inner shaft (14) within the axial opening of the outer shaft (12) by a wedging force provided by the engagement of the sleeve (30) with the tapered axial opening.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

[0001] The present invention relates generally to a leg for supporting a structure, and more particularly to a support leg that is adjustable in the vertical direction to easily adjust the height of the structure being supported.

[0002] The support leg can be used to support, for example, a table or multiple shelves. The number of legs needed to support such structure can vary from one, two, three, four, or more, depending on the size, design, and shape of the structure and its environment.

[0003] One aspect of the present invention makes use of a mounting assembly of the type disclosed U.S. Patent No. 3,523,508 (Maslow). The mounting assembly in that patent is used in conjunction with an adjustable shelving system comprising a formed-wire shelf component having a frustoconically shaped collar at each corner for receiving a support post. Each collar tapers outwardly toward its lower extremity when viewed in normal use. Generally cylindrical support posts, each having a plurality of uniformly spaced annular grooves formed in its outer surface, are secured to the shelf by the mounting assembly. Each mounting assembly comprises at least two separate mounting members which are joined about and at least partially surround the support post to define a unitary sleeve having an complementary frustoconically shaped outer surface. Thus, the mounting sleeve is thickest at its bottom portion than at its top. The sleeves are sized to fit snugly within the shelf collars. An annular rib formed on an inside surface of each sleeve is sized to engage the annular groove formed on the support post.

Description of the Prior Art

[0004] Vertically adjustable legs for supporting various types of structures have been known for many years. For example, U.S. Patent No. 2,705,119 (Ingwer) discloses a pipe support stand that is adjustable in the vertical direction. An inner column having a series of spaced annular grooves is supported within a hollow outer pipe. Steel balls are supported in holes in the outer pipe by a ring and serve to secure the inner column by engaging one of the annular grooves. The steel balls are released from the engaged annular groove by sliding the ring to allow the inner column to be vertically adjusted. When the inner column is set at the desired height the ring is manipulated to bias the steel balls into engagement with another annular groove.

[0005] Another prior art example is provided in a footrest mounting assembly disclosed in U.S. Patent No. 3,458,234 (Bates). This patent discloses a compressible plastic sleeve that is disposed around a vertical tube for supporting a seat. The outer face of the sleeve is tapered to have a wider lower end and slidably carries thereon an annular collar with a similar tapering or frustoconical shape. The collar forms the central part of a footrest that is supported on the tube by compressing the sleeve around the tube. To adjust the height of the footrest, the collar is lifted slightly to release the compressive force on the sleeve, and both the sleeve and collar can be moved up or down the tube to the desired height.

[0006] While systems such as those discussed above are known, further improvements in vertically adjustable support legs are desirable.

SUMMARY OF THE INVENTION

[0007] It is an object of the present invention to provide a vertically adjustable support leg that improves upon supporting legs known in the art. It is another object of the present invention to provide improvements that utilize a relatively simple and uncomplicated structure that provides significant strength, reliability and load-supporting capability.

[0008] It is still another object of the present invention to provide a vertically adjustable support leg that is readily adjusted with minimal effort, without tools, and provides high strength, stability and rigidity.

[0009] It is yet another object of the present invention to provide a simple and economical means for providing a vertically adjustable supporting leg that can support substantial loads.

[0010] In accordance with one aspect of the invention, the vertically adjustable supporting leg comprises an outer shaft having an axial opening at one end, and an inner shaft shaped to fit telescopically within the axial opening of the outer shaft. A sleeve is mounted about the inner shaft for securing the inner shaft within the axial opening of the outer shaft and can include engaging means for engaging the inner shaft.

[0011] In accordance with another aspect of the invention, the sleeve is comprised of two mounting members with a frustoconically shaped outer surface. The axial opening in the first leg has a complementary-shaped frustoconical surface for radially compressing the sleeve about the inner shaft and securing the inner shaft within the outer shaft.

[0012] In accordance with still another aspect of the invention, a supporting leg comprises a first leg having a first diameter and an axial opening at one end, a second leg having a second diameter smaller than the first diameter and insertable telescopically into the axial opening, and a sleeve mountable at different heights on the second leg for securing the second leg within the axial opening of the first leg.

[0013] These and other objects, aspects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiment taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 

Figure 1 is a vertical cross-sectional view of the vertically adjustable support leg in an assembled state in accordance with the present invention; and

Figure 2 is a perspective view, partially in vertical cross-section, of the elements comprising the vertically adjustable support leg in an unassembled state in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] For convenience, the support leg of the present invention will be described in this specification and set forth in the concluding claims as if it is in a vertical attitude.

[0016] A vertically adjustable support leg 10 in accordance with the subject invention is shown in Figure 1. The support leg comprises a first leg section, or outer shaft, 12 and a second leg section, or inner shaft, 14 insertable telescopically into an axial opening 16 in the bottom of the outer shaft.

[0017] The outer shaft is preferably circular in cross-section and includes a plurality of spaced annular grooves 18 provided on its outer surface. The top end of the outer shaft extends upwardly to support, for example, a table top or the outer shaft can support one or more structures such as shelves in the manner described, for example, in U.S. Patent No. 3,523,508 (Maslow), which is incorporated herein by reference.

[0018] The axial opening 16 of the outer shaft, as best seen in Figure 2, is designed to receive the upper end of the inner shaft 14. This axial opening, described in detail below, may be formed integrally with the outer shaft or may be formed as a separate insert member as shown in the Figures, which is received in the lower end of the outer shaft. A lower portion of the axial opening 16 has a frustoconically shaped, or tapered, surface 20 with a widest opening 22 at the bottom end of the outer shaft. The upper portion of the axial opening is sized slightly larger than the outer diameter of the inner shaft. The portion of the outer shaft 12 that extends above the axial opening can be hollow to reduce the weight and cost of the supporting leg.

[0019] The inner shaft 14 is also preferably cylindrical, hollow and includes, at least at its upper end, a series of preferably regularly spaced annular grooves 24.

[0020] The inner shaft 14 is farmed to be telescopically inserted into the axial opening 16 of the outer shaft 12 and secured therein by a mounting assembly, or sleeve, 30. As best seen in Figure 2, the sleeve 30 is comprised of two separate, complementary sleeve members 32 and 34, each formed with a cylindrical inner surface and an annular interior rib 31 for engaging any one of the annular grooves 24 on the outer surface of inner shaft 14. Each assembled sleeve 30 has a downwardly, outwardly frustoconically shaped exterior surface 40. The frustoconical shape of the surface of the sleeve 30 is seen in Figure 1 to generally correspond to or complement the frustoconical inner surface 20 of the axial opening in the outer shaft 12.

[0021] The vertical edges of each sleeve are formed with a respective tongue 36 and 38 groove arrangement. The tongue and groove of each sleeve member complement the same arrangement on the other sleeve member. Further, each sleeve member 32 and 34, in cross section extends around in inner shaft by more than 180 degrees, thereby to embrace the shaft.

[0022] Thus the sleeve members may be assembled around the inner shaft to define the unitary sleeve 30 that tapers outwardly toward its lower extreme when viewed in normal use, that is, it is thicker at its bottom than at its top. The sleeve may be secured to the inner shaft 14 at increment positions by engagement of the ribs 31 in one of the grooves 24, with the a tapered exterior mating surface 40 prepared to engage the frustoconical surface 20 of the axial opening.

[0023] The outer shaft and inner shaft can be made of metal or plastic, and the sleeve is preferably made of a plastic polymeric material. Additionally, while described as cylindrical, the shafts may have other cross-sectional shapes without departing from the teaching of the subject invention. Still further, the sleeve 30 may be formed as a one piece member or as two portions hinged together, for example, by a "living-hinge."

[0024] To assemble the supporting leg, the sleeve members are placed about the inner shaft 14 such that the annular rib 31 formed by their assembly on their inside surface engages a groove 24 on the inner shaft at the desired height. The inner shaft with the sleeve mounted thereon is then inserted into the axial opening until the sleeve firmly grips the inner shaft by virtue of a compressing force supplied by engaging the frustoconical surfaces 20 of the axial opening and complementary surface 40 of the sleeve. This arrangement is shown best in Figure 1.

[0025] The load from the outer shaft and, when the supporting leg is positioned for use, the supported structure produces a wedging action between the tapered exterior mating surface 40 of the sleeve and the frustoconically surface 20 in the axial opening. The wedging action provides a radially inwardly directed force to bring the sleeve 30 into a locking relation with the inner shaft 14, and an outwardly directed force is exerted by the sleeve on the surface 20 in the axial opening to secure the inner shaft within the outer shaft. As the load supported by the leg increases, both the radially inwardly directed force and the outwardly directed force increase.

[0026] To adjust vertically the height of the leg, the outer shaft and the inner shaft are forced axially in opposite directions relative to each other to relieve the wedging force and allow the inner shaft and sleeve to be withdrawn from the axial opening of the outer shaft. The sleeve can be repositioned to engage a different groove on the inner shaft and then inserted back into the axial opening of the outer shaft as discussed above.

[0027] As shown in Figure 1, an adjustable foot pad 26 can be threadedly engaged with the bottom of the inner shaft 14 in conventional fashion to permit minor height adjustment of the supporting leg, independent of the gross adjustment provided by the locking sleeve-axial opening configuration of the present invention.

[0028] An optional removable locking ring 42, shown in phantom view in Figure 1, or comparable locking means can be provided to secure the sleeve within the axial opening and prevent the inner and outer shafts from relative axial movement in opposite directions. In this manner, the assembled structure can be lifted off the ground without the possibility of the inner shaft sliding out of the outer shaft.

[0029] Accordingly, it will be appreciated that the present invention provides a novel supporting leg that can easily and reliably be adjusted in the vertical direction to change the length of the leg. The tapered sleeve can be removably mounted at different heights on the inner shaft and then secured by a wedging action when the inner shaft is inserted into the tapered axial opening of the outer shaft. For these and other reasons described above in detail, the present invention provides substantial improvements over known vertically adjustable supporting legs.

[0030] Although a specific embodiment of the present invention has been described above in detail, it will be understood that this description is merely for purposes of illustration. Various modifications of and equivalent structures corresponding to the disclosed aspects of the preferred embodiment in addition to those described above may be made by those skilled in the art without departing from the spirit of the present invention which is defined in the following claims, the scope of which is to be accorded the broadest interpretation so as to encompass such modifications and equivalent structures.

Claims

1. A vertically adjustable support leg, comprising:
   an outer shaft (12) having an axial opening (16) in one end;
   an inner shaft (14) shaped to be telescopically received within the axial opening of said outer shaft; and
   a sleeve (30) mountable about said inner shaft for securing said inner shaft within the axial opening of said outer shaft, said sleeve being positionable at different locations along the length of said inner shaft.

2. A vertically adjustable support leg according to claim 1, wherein the axial opening (16) in said outer shaft (12) has a frustoconical surface (20) with its widest portion (22) at the one end of said outer shaft.

3. A vertically adjustable support leg according to claim 2, wherein said sleeve (30) has a frustoconical shape tapering (40) to a widest portion at its lower end when mounted about said inner shaft (14).

4. A vertically adjustable support leg according to claim 3, wherein said inner shaft (14) is secured within the axial opening (16) of said outer shaft (12) by a wedging action between said tapered sleeve (30) and said frustoconical surface (20) of the axial opening.

5. A vertically adjustable support leg according to claim 1, wherein said inner shaft (14) has a plurality of spaced annular grooves (24) on its outer surface.

6. A vertically adjustable support leg according to claim 5, wherein said sleeve (30) comprises at least one mounting sleeve member (32, 34) formed to embrace said inner shaft (14), said mounting sleeve member (32, 34) having an interior rib (31) formed to be received in any one of the grooves (24) in said inner shaft (14).

7. A vertically adjustable support leg according to claim 1, wherein said sleeve (30) comprises two mounting sleeve members (32, 34) each having a tongue (36) and a groove (38) respectively on opposing vertical edges thereof, the tongue and groove of each sleeve members being configured to engage the respective groove and tongue of the other sleeve member.

8. A vertically adjustable support leg according to claim 7, wherein each said mounting sleeve member (32, 34) includes an interior rib (31) and said inner shaft (14) includes a plurality of spaced grooves (24), said rib being engageable in any one of the grooves at selected heights on said inner shaft.

9. A vertically adjustable support leg according to claim 1, further comprising a foot pad (26) adjustably mounted in the bottom end of said inner shaft (14).

10. A vertically adjustable support leg according to claim 1, further comprising locking means for preventing said inner shaft (14) and said outer shaft (12) from axial movement in an opposite direction relative to each other.

11. A support leg, comprising:
   a first leg member (12) having a first diameter and an axial opening (16) in one end;
   a second leg member (14) having a second diameter smaller than the first diameter and telescopically insertable into the axial opening; and
   a sleeve (30) mountable at different locations on said second leg for securing said second leg within the axial opening of said first leg.

12. A support leg according to claim 11, wherein the axial opening (16) in said first leg (12) has a frustoconically shaped surface (20) with its widest portion (22) at the one end of said first leg.

13. A supporting leg according to claim 12, wherein said sleeve (30) has a frustoconical shape tapering (40) to a widest portion at its lower end when mounted about said second leg (14).

14. A support leg according to claim 13, wherein said second leg (14) is secured within the axial opening (16) of said first leg (12) by a wedging action between said tapered sleeve (30) and said frustoconical surface (20) of the axial opening.

15. A support leg according to claim 11, wherein said second leg (14) has a plurality of spaced annular grooves (24) on its outer surface.

16. A support leg according to claim 15, wherein said sleeve (30) comprises at least one mounting sleeve member (32, 34) formed to embrace said inner shaft (14), said mounting sleeve member having an interior rib (31) formed to be received in any one of the grooves (24) in the second leg.

17. A support leg according to claim 11, wherein said sleeve (30) comprises two mounting sleeve members (32, 34) each having a tongue (36) and a groove (38) respectively on opposing vertical edges thereof, the tongue and groove of each sleeve member being configured respectively to engage the groove and tongue of the other sleeve member.

18. A support leg according to claim 17, wherein each said mounting sleeve member (32, 34) includes an interior rib (31) and said second leg (14) includes a plurality of spaced annular grooves (24), said rib being engageable in one of the grooves at selected heights.

19. A supporting leg according to claim 11, further comprising a foot pad (26) adjustably mounted in the bottom end of said second leg (14).

20. A support leg according to claim 11, further comprising locking means for preventing said first leg (12) and said second leg (14) from axial movement in an opposite direction relative to each other.

Drawing