Adjustable tripod stand

Abstract: An adjustable tripod stand (10) having independently adjustable legs comprising an upright portion (11) for supporting an object at its upper end, independently movable collar members (15,16) slidably mounted on the upright portion which are longitudinally adjustable relative to one another and to the upright portion for selective positioning, releasable fasteners on the collars for securing them to the upright portion (11) at selected positions, and movable leg members (29) operatively connected at their upper ends to different ones of the collar members and independently movable by the collar members for selective independent longitudinal positioning and radial extension relative to the upright portion (11) and to one another. The stand may be erected in limited or confined areas, on multi-level surfaces, and level surfaces, and the positioning of said collars allows the longitudinal axis of the stand to be disposed in an off-vertical axis position for positioning the centre of gravity of the supported article relative to the centre of the supporting legs. The stand may also include a support member (32) telescoped inside the upright portion (11) and a fastener releasably securing the telescoping members together and comprising a clamp member (38), a lever member (47) pivotally mounted on the clamp member with a multi-planar camming surface at the upper end and a resilient member disposed between the clamp member and a lever hand grip portion, and having a camming surface sectioned into three distinct angular planes, such that the support member is more easily supported at and released from different positions.

Description: Background of the Invention Field of the Invention This invention relates generally to tripod stands, and more particularly to an adjustable tripod stand for supporting various articles which has independently adjustable movable legs. Brief Description of the Prior Art Because of their size, weight, portability and ease and speed of deployment, tripod stands are desirable for supporting various articles and instruments since they provide selective height adjustment and a stable support. They are particularly useful in supporting such things as cameras, video equipment, telescopes, surveying instruments, and musical instruments. Some tripod stands have legs which may be adjusted in length to maintain the supported article in a level position on uneven ground but the legs are not independently adjustable relative to one another and to the vertical support member, thus the centre of gravity may be off-axis. In other words the vertical portion of the stand cannot be oriented in an off-axis position and still maintain the centre of gravity for a stable support system. Another problem with conventional tripod stands is that the legs are not particularly suited for reducing the perimeter of the support base and still provide a stable support system when placing the legs in close or confined areas and on multi-level surfaces. There are several patents which describe various adjustable tripod stand devices. Viken, U.S. Patent 1,795,747 discloses a tripod having collapsible legs with an extensible support composed of three telescoping members slidably supported by the legs. Bogar, U.S. Patent 3,307,814 discloses a stand for instruments of the type having a box-like casing. The stand has telescopically adjustable legs or vertical tubular upright members and a tray at the top of the uprights. Boehm, U.S. Patent 3,570,130 discloses a holding device for surveying instruments which includes a channel-like mounting bracket with a pair of instrument gripping clamps and a pair of adjustable legs thereon which co-operate with the instrument to form a tripod type support for supporting the instrument in a reference position. GIBRAN, US patent 4,215,839 discloses a tripod for support of a camera or other apparatus including a central column having slots extending longitudinally of the column in which the upper end of tripod legs are slidable. Summary of the Invention It is therefore an object of the present invention to provide an adjustable tripod stand for supporting articles which has independently adjustable movable legs. It is another object of this invention to provide an adjustable tripod stand for supporting articles which allows for multiple angularities and tripod configurations. Another object of this invention is to provide an adjustable tripod stand for supporting articles which allows the body of the stand to be oriented in an off-axis position and still maintain the centre of gravity in a stable support system. A further object of this invention is to provide an adjustable tripod stand for supporting articles which is simple in construction, economical to manufacture, and rugged and reliable in use. A further object of this invention is to provide a tripod stand having a novel adjustable support and release mechanism. Other objects of the invention will become apparent from time to time throughout the specification and claims as hereinafter related. Brief Description of the Drawings Figure 1 is an elevation view of a preferred adjustable tripod stand in accordance with one embodiment of the present invention. Figure 2 is a transverse cross-section through the lower portion of the adjustable tripod stand taken along line 2-2 of Figure 1. Figure 3 is a partial elevation view of the stand of Figure 1 shown with the legs adjusted for placement on a multi-level surface. Figure 4 is a partial elevation view of an embodiment of a leg member having casters at the bottom end. Figure 5 is an elevational view of the stand having its legs adjusted to position the centre of gravity of the supported article within the support base. Figure 6 is a transverse cross-section through the leg support upper collar member of the stand of Figure 1. Figure 7 is a transverse cross-section through the leg brace support lower collar member of the stand of Figure 1. Figure 8 is a transverse cross-section through the inner and outer tubular members of the stand of Figure 1. Figure 9 is a longitudinal cross-section through the bottom portion of the inner and outer tubular members of the stand of Figure 1. Figures 10 - 12 are longitudinal cross-sections illustrating the latch clutch mechanism of the stand of Figure 1. Description of a Preferred Embodiment Referring to the drawings by numerals of reference, there is shown in Figures 1 - 5, a preferred adjustable tripod stand 10 having a longitudinal upright portion 11 formed of telescoping tubular members. The lower section of the upright portion 11 comprises an elongate outer tubular member 12 having a plurality of circumferentially spaced grooves extending longitudinally on its exterior surface. Referring additionally to Figures 6 - 8, in the illustrated embodiment, four grooves are shown, two diametrically opposed grooves 13 being generally U-shaped in cross-section, and the other two diametrically opposed grooves 14 being dovetail shaped in cross-section. As seen in Figures 6 and 7, a pair of semi-circular upper leg support collar members 15 and 16 and a pair of semi-circular leg brace support collar members 17 and 18 are slidably mounted on the outer tubular member 12. Each of the collar members 15, 16, 17, and 18 are semi-circular in cross-section with the longitudinal edges 19 bent inwardly to be received within the longitudinal grooves 13. A semi-circular sleeve element 20 is installed between the exterior of the outer tubular member 12 and the interior of each collar segment. The sleeve element 20 is of a low friction material, such as nylon, to facilitate sliding movement of the collar segments on the outer tubular member. A pair of wedge elements 21 are slidably received within the dovetail grooves 14 inwardly adjacent to each of the collar segments. Each wedge 21 is slightly smaller in cross-section than the dovetail groove 14. A hole 22 extends radially through the side wall of each collar segment and each sleeve and each wedge 21 has a threaded stud 25. Wing nuts 23 are provided which have a shank portion 24 internally threaded to fit stud 25. When the wing screw 23 is loosened, the wedge 21, collars 15, 16, and sleeves 20, are free to slidably move as a unit longitudinally on the outer tubular member 12 but are captured on the outer member by the wedge 21 retained in the dovetail groove 14 and the edges 19 of the collars 15 and 16 retained within the grooves 13. Thus each collar 15 and 16 are independently movable relative to one another and the outer tubular member. When the wing screw 23 is tightened, its shoulder 26 engages the exterior of the collar and the wedge 21 is drawn into firm engagement on the angular sides of the dovetail groove 14, thus locking the collars 15 and 16 in a desired position on the outer tubular member 12. The leg brace support collar members 17 and 18 are substantially similar in construction and operation to the upper leg support collar members 15 and 16 (Figure 7). Each collar segment 17 and 18 is semi-circular in cross-section with the longitudinal edges 19 bent inwardly to be received within the longitudinal grooves 13, each has a semi-circular sleeve element 20 installed between the exterior of the outer tubular member 12 and the interior of each collar segment bore, and are connected by wing screws 23 to slidably move independently on the outer tubular member 12 as described above. Thus, each collar 15, 16, 17, and 18 is independently movable relative to one another and the outer tubular member, and each may be locked in a desired position on the outer tubular member 12. As best seen in Figures 6 and 7, the upper leg support collar members 15 and 16 have integral tongues 27 projecting radially from their exterior and the leg brace support collar members 17 and 18 have integral yokes 28 projecting radially from their exterior. In the illustrated embodiments, there are two circumferentially spaced tongues 27 on the collar segment 15, and one tongue on the collar segment 16, and two yokes 28 on the collar segment 17 and one yoke on the collar segment 18. The yokes and tongues are equally spaced apart circumferentially for mounting three legs thereon. Although three tongues and three yokes are illustrated, it should be understood, that more than three may- be provided for mounting more than three legs. The upper end of a leg member 29 is pivotally mounted on each tongue 27 and a leg brace member 30 is pivotally mounted at one end in each yoke 28. The free end of the leg brace 30 is pivotally connected to the leg member 29 intermediate its ends. A foot pad 31 formed of resilient material is provided on the bottom end of each leg member. It should be understood that the bottom end of each leg member 29 may also be provided with a wheel or caster 31A as seen in Figure 4. As seen in Figures 1, 3, and 5, when the upper leg collar segments 15 and 16 and leg brace collar segments 17 and 18 are positioned across from one another respectively, the bottom of the legs will extend radially an equal distance from the centre of the tubular member 12. If one of the upper leg collar segments 15 or 16 and its corresponding leg brace collar segment 17 or 18 are moved towards each other on the tubular member 12, the bottom of the leg(s) connected thereto will be extended radially outward to be positioned an unequal distance from the centre of the tubular member 12 relative to the other leg(s). If one of the upper leg collar segments 15 or 16 and its corresponding leg brace collar segment 17 or 18 are moved away from each other on the tubular member 12, the bottom of the leg(s) connected thereto will be drawn radially inward to be positioned an unequal distance from the centre of the tubular member 12 relative to the other leg(s) (Figure 5). This allows for placement of the stand in limited or confined areas. If the legs are supported on a level surface, this adjustment will cause the longitudinal, vertical axis of the stand to be disposed in an off-vertical axis position for placing the centre of gravity of the supported article relative to the centre of the supporting legs (Figure 5). This adjustment also provides a minimum or maximum peripheral support base. As seen in Figure 3, in addition to the adjustment described above, the upper leg support collars 15 and 16 and the leg brace collars 17 and 18 may be positioned in vertically spaced pairs relative to the other vertically spaced pair. For example, one of the upper leg collar segments 15 or 16 and its corresponding leg brace collar segment 17 or 18 may both be moved upward on the tubular member 12 relative to the other pair and the bottom of the leg(s) connected to the upper pair will be raised d relative to the other leg(s). As described above, the legs may also be extended radially inward and outward. This allows for placement of the stand on an uneven or multi-level surface or platform and also in limited or confined areas. The legs may be adjusted relative to an uneven or multi-level surface to cause the vertical axis of the stand to be disposed in an off-vertical axis position for placing the centre of gravity of the supported article relative to the centre of the supporting legs even if they are at different heights. An elongate inner tubular member 32 is slidably received within the outer tubular member 12. As seen in Figure 8, the outer tubular member 12 may have a pair of diametrically opposed U-shaped grooves 33 extending longitudinally on its interior surface and the lower end of the inner tubular member 32 may be provided with a rod or pin 34 extending transversely through its side wall. The outer ends of the rod or pin 34 are received within the opposed grooves 33 to prevent relative rotary movement between the inner and outer tubular members but allowing relative longitudinal movement. As shown in Figure 9, the bottom end of the outer tubular member 12 may be enclosed by an end cap 35 secured therein by a set screw 36 or other conventional means. This causes air to be trapped within the tubular members and to escape slowly through the clearance annulus between the tubular members if the inner tubular member is suddenly released. In other words, the air within the upright portion of the stand acts as a shock absorber and allows the inner tubular member to descend slowly in the event that it is suddenly or accidentally released. In normal assembly conditions, the top end of the inner tubular member, or a subsequent upper tubular member is provided with an end fitting which substantially closes off the top end of the upright members. However, to facilitate the shock absorber effect, the open bottom end of the inner tubular member 32 may have a plug 37 whereby it would act as a loosely fitting piston within the outer tubular member 12. Referring now to Figures 1 and 10 - 12, a clamp member 38 is mounted on the top end of the outer tubular member 12. Clamp member 38 has a generally cylindrical body 39 with a bore 40 extending from the bottom end and terminating in a reduced diameter intermediate bore 41 forming a circumferential shoulder 42 therebetween and the intermediate bore 41 terminates in a smaller bore 43 at the top end of the clamp body. The bore 40 is slightly larger than the outside diameter of the outer tubular member 12 to be slidably received thereon, and the smaller bore 43 is slightly larger than the outside diameter of the inner tubular member 32 allowing it to pass slidably therethrough. The shoulder 42 engages the top end of the outer tubular member 12 and the intermediate bore 41 is larger than the outside diameter of the inner tubular member 32 defining an annulus therebetween. The clamp member 38 is secured to the top of the outer tubular member 12 by a set screw 44 or other conventional means. A longitudinal slot 45 extends along one side of the clamp body 39 and an opening 46 extends laterally between the intermediate bore 41 and the slot 45. A lever member 47 having a hand grip portion 48 with an inwardly facing camming surface 49 at the upper end thereof is pivotally supported on a pin 50 within the slot 45. A compression spring 51 has one end engaged in the clamp body 39 and its other end engaged on the hand grip portion 48 of the lever 47. The inner face of the camming surface 49 is divided into three angular planes A, B, and C. Figure 10 shows the clamp member 38 with its lever 47 in an intermediate position wherein the middle angular plane B of the camming surface 49 is engaged on the exterior of the inner tubular member 32. The spring 51 provides sufficient force to frictionally engage the middle angular plane B with the inner tubular member 32 whereby the inner tubular member is maintained at the selected height under normal support conditions but may be rotated without gripping the lever, upon application of sufficient force to overcome the frictional engagement. In this case, the clamp member 38 acts as a friction clutch. Figure 11 shows the clamp member 38 with lever 47 in an unlocked position wherein the hand grip portion 48 is squeezed inward to align the lower angular plane C of the camming surface 49 substantially parallel to the exterior of the inner tubular member 32. In this position, the inner tubular member 32 slides freely through the clamp member as long as the lever 47 is pressed inward. When the lever 47 is released, the spring 51 returns the lever to the intermediate position to frictionally engage the middle angular plane B with the inner tubular member as described above. Figure 12 shows the clamp member 38 with its lever 47 in an upper or locked position wherein the hand grip portion 48 is pivotally raised past the intermediate position to forcefully engage the upper plane A of camming surface 49 with the exterior of inner tubular member 32. In other words, the upper angular plane A of camming surface 49 is wedged against the exterior of the inner tubular member 32. In this position, the inner tubular member 32 is securely locked at the selected height under heavy support conditions to prevent accidental or unexpected longitudinal movement. Referring again to Figure 1, a third tubular member 52 may be slidably received inside the inner tubular member 32 and a conventional split clamp member 53 having the usual bolt and wing nut 54 to may be secured at the upper end of the inner tubular member 32 to clamp the third tubular member 52 at a desired height. A conventional inverted L-shaped clamp member 55 having the usual bolt and wing nut 56 may also be installed on the exterior of third tubular member 52 and engaged on the clamp 53 to maintain the upper portion of the upper upstanding members at the desired circumferential orientation relative to the base portion. Similarly, the top portion of the stand may be provided with various conventional tripod mounting hardwarc for mounting a variety of articles and instruments such things as camera, video equipment, telescopes, surveying instruments, and musical instruments. It should be understood that the particular tripod stand illustrated has a top portion configured to support musical cymbals, however other top portions may be provided for supporting such things as cameras, video equipment, telescopes, surveying instruments and the like. While this invention has been described fully and completely with special emphasis upon a preferred embodiment, it should be understood that within the scope of the appended claims the invention may be practised otherwise than as specifically described herein.

Claims: An adjustable tripod stand (10) comprising: an upright portion (11) for supporting an object at its upper end, a plurality of independently moveable collar members (15,16,17,18) slidably mounted on said upright portion and longitudinally adjustable relative to one another and to said upright portion (11) for selective positioning thereon, said collar members (15,16,17,18) being moveable past each other on said upright portion (11), releasable fastening means (23) on said collar members (15,16,17,18) for securing the same to said upright portion (11) at selected positions, and a plurality of independently moveable legs comprising a leg portion (29) and a leg brace member (30), wherein one end of a respective leg brace member (30) is pivotally connected to the associated leg portion (29) intermediate its ends and the other end is pivotally connected to a moveable collar member (17,18) said plurality of moveable leg portions being pivotally connected at their upper ends to different ones of said collar members and operable on independent movement of said collar members for selective independent longitudinal positioning and radial extension relative to said upright portion (11) and to one another for supporting said upright portion (11) whereby said stand (10) may be erected in limited or confined areas, on multi-level surfaces and on level surfaces, and the positioning of said collar members (15,16,17,18) allows the longitudinal axis of the stand (10) to be disposed in an off-vertical axis position for positioning the centre of gravity of the supported article relative to the centre of the supporting legs. An adjustable tripod stand (10) according to Claim 1 characterised in that said upright portion (11) comprises telescoping tubular members (12, 32) longitudinally extensible relative to each other, and including fastening means on said upright portion (11) for releasably securing said telescoping tubular members (12, 32) together in a selected position. An adjustable tripod stand (10) according to Claim 1 or Claim 2 characterised in that at least one leg brace support collar (17, 18) disposed beneath said upper leg support collar (15, 16) and having brace support means (28) for pivotally supporting the extended end of at least one said leg brace member (30), such that when said upper leg support collar (15, 16) and the corresponding said leg brace collar (17, 18) are moved towards each other on said upright portion (11) the bottom of said leg (29) connected thereto will be extended radially outward to be positioned an unequal distance from the centre of the upright portion (11) relative to the other legs (29), and when said upper leg support collar (15, 16) and the corresponding said leg brace collar (17, 18) are moved away from each other on said upright portion (11) the bottom of said leg (29) connected thereto will be drawn radially inward to be positioned an unequal distance from the centre of the upright portion (11) relative to the other legs (29). An adjustable tripod stand (10) according to Claim 3 characterised in that the upper portion of said at least one leg member (29) is pivotally and releasably connected to said upper leg support collar (15, 16), and the extended end of said leg brace (30) is pivotally and releasably connected to said leg brace support collar (17, 18) disposed beneath said upper leg support collar (15, 16), whereby, at least one said leg member (29) and its said leg brace member (30) may be removed from a vertically spaced upper leg support collar (15, 16) and leg brace support collar (17, 18) and pivotally and releasably connected to a differently spaced upper leg support collar (15, 16) and leg brace support collar (17, 18), such that said at least one leg member (29) may be selectively positioned vertically relative to the other said leg members (29). An adjustable tripod stand (10) according to any of the above claims characterised in that said upright portion (11) includes an elongate tubular member (12) having a plurality of circumferentially spaced grooves (13, 14) extending longitudinally on its exterior surface and, said collar members (15, 16, 17, 18) are operatively connected with said grooves (13, 14) to slide longitudinally therein. An adjustable tripod stand (10) according to Claim 5 characterised in that said grooves (13, 14) include at least two diametrically opposed grooves each having a generally U-shaped cross-section (13), said upper leg support collar (15, 16) and said leg brace support collar (17, 18) each comprise at least two semi-cylindrical collar segments slidably mounted on said outer tubular member (12) and having inwardly facing longitudinal edges (19) received within said U-shaped longitudinal grooves (13), and each said semi-cylindrical collar segment is independently moveable relative to one another and to said outer tubular member (12) and each may be secured in a desired position on said outer tubular member (12), such that when one said upper leg support collar segment (15, 16) and the corresponding said leg brace collar segment (17, 18) are moved towards each other on said outer tubular member (12) the bottom of said leg (29) connected thereto will be extended radially outward to be positioned an unequal distance from the centre of the upright portion (11) relative the other other legs (29), and when said upper leg support collar segment (15, 16) and the corresponding said leg brace collar segment (17, 18) are moved away from each other on said outer tubular member (12) the bottom of said leg (29) connected thereto will be drawn radially inward to be positioned an unequal distance from the centre of the upright portion (11) relative to the other legs (29). An adjustable tripod stand (10) according to Claim 6 characterised in that at least one said semi-cylindrical upper leg support collar segment (15, 16) and its corresponding semi-cylindrical leg brace support collar segment (17, 18) may be selectively positioned vertically different relative to other said semi-cylindrical upper leg support collar segments (15, 16) and their corresponding leg brace support collar segments (17,18). An adjustable tripod stand (10) according to any of the above claims characterised in that said stand (10) includes a semi-cylindrical sleeve element (20) disposed between the exterior of said outer tubular member (12) and the interior of each said collar segment (15, 16,17, 18) to facilitate sliding movement of said collar segments (15, 16, 17,18) on said outer tubular member (12). An adjustable tripod stand (10) according to any of the above Claims characterised in that said grooves (13,14) include at least two diametrically opposed grooves each have a generally dovetail cross-section (14), and said releasable fastening means on said collars (15, 16, 17, 18) for securing same to said upright portion (11) at selected positions comprises: a wedge element (21) having a generally dovetail cross-section slightly smaller than said dovetail groove (14) slidably received within said dovetail groove (14) inwardly adjacent to each said semi-cylindrical collar segment (15, 16, 17, 18) and connected to each said segment by wing screws (23) extending radially through the side wall of each said collar segment (15, 16, 17, 18), whereby upon loosening said wing screw (23), said wedge (21), collar segment (15, 16, 17, 18), and sleeve (20) are free to slidably move as a unit longitudinally on said outer tubular member (12) but are captured on said outer member (12) by said wedge (21) retained in said dovetail groove (14), and upon tightening said wing screw (23), said wedge (21) is drawn into film engagement on the angular sides of said dovetail groove (14) to lock said collar member (15, 16, 17, 18) in a desired position on said outer tubular member (12). An adjustable tripod stand (10) according to claim 2 characterised in that said upright portion (11) includes said fastening means for securing the telescoping members comprising a clamp member (38) mounted on the top end of said outer tubular member (12) and having a bore (40) at its upper end to slidably pass said inner tubular member (32) therethrough, a level member (47) pivotally mounted on said clamp member (38) and having a camming surface (49) at the upper end thereof and resilient means disposed between said clamp member (38) and a lever hand grip portion (48), said lever camming surface (49) being disposed adjacent said inner tubular member (32) and sectioned into three angular plans (A, B, C), such that when said lever (47) is in an intermediate position, said resilient means will provide sufficient force to frictionally engage and grip a middle angular plane (B) of said camming surface (49) on the exterior of said inner tubular member (32) whereby said inner tubular member (32) is maintained at a selected height under normal support conditions but may be moved longitudinally without gripping the lever (47) upon application of sufficient axial force to overcome the frictional engagement, when said lever hand grip portion (48) is pressed inward to an unlocked positioned, a lower angular plane (C) of said camming surface (49) is aligned substantially parallel with said inner tubular member (32) such that said inner tubular member (32) slides freely through said clamp member (38) as long as said lever (47) is pressed inward and when released said resilient means returns said lever (47) to the intermediate position, and when said lever (47) is pivotally raised to a locked position, an upper angular plane (A) of said camming surface (49) is forcefully engaged on the exterior of said inner tubular member (32) such that said inner tubular member (32) is securely locked at a selected height under heavy support conditions to prevent accidental or unexpected longitudunal movement. An adjustable tripod stand (10) according to any of the above claims characterised in that said upright portion (11) includes an enlogate outer tubular member (12) and an elongate inner member (32) slidably received therein. An adjustable tripod stand (10) according to any of the above Claims characterised in that the lower end of said outer tubular member (12) is substantially enclosed sufficient to trap air within the tubular members (12, 32) and allow it to escape slowly through the clearance annulus between the tubular members (12, 32) upon sudden longitudinal movement of said inner tubular member (32) relative to said outer tubular member (12) to serve as an air cushion which allows said inner tubular member (32) to descend slowly in the event that it is suddenly or accidently released. An adjustable tripod stand (10) according to any of the above Claims characterised in that said outer tubular member (12) has a pair of opposed grooves (33) extending longitudinally along its interior surface, and the lower end of said inner tubular member (32) has a pin (34) extending transversely through its side wall, the outer ends of which are received within said opposed grooves (33) to prevent relatively rotary movement between said inner and outer tubular members (32, 12) but allowing relative longitudinal movement. An adjustable tripod stand (10) according to any of the above Claims characterised in that a releasable connection between said at least one leg members (29) and its brace member (30) and one of said collars (15, 16, 17, 18) comprises an apertured tongue (27) on one and an apertured yoke (28) on the other, a bolt extending through said apertures, and a nut releasably holding said bolt.

Inventors: MAY RANDALL LEE, MAY, RANDALL LEE
Applicants: MAY RANDALL LEE, MAY, RANDALL LEE
Application year: 1991
Main classification: F16M11
IPC codes: F16M11