Supports – Stand – Plural leg
Reexamination Certificate
2000-04-03
2001-09-11
Braun, Leslie A. (Department: 3632)
Supports
Stand
Plural leg
C248S169000, C248S170000, C248S163100, C248S166000, C248S177100, C248S188000
Reexamination Certificate
active
06286795
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to equipment support tripods, and more particularly concerns dual-stage adjustable length tripod legs.
BACKGROUND OF THE INVENTION
Various types of tripods exist for supporting cameras or other equipment during use. Single stage tripods include legs which have two portions which telescope relative to one another to adjust the total length of the leg, while dual stage tripods include legs having three telescoping portions. Although single stage tripods are more versatile than non-adjustable tripods, dual stage tripods provide an added level of control and adjustability over single stage tripods.
The separate, telescoping portions of a leg are coupled together by a lock assembly to prevent relative movement when the supported equipment is in a desired position. The lock assembly is generally secured to the end of one leg portion and slidingly engages the second leg portion. For example, the lock assembly of a single stage tripod leg is typically secured to the lower end of the upper leg portion, and slidingly receives the lower leg portion. When the telescoping leg portions reach their desired position, the lock assembly is engaged to couple the upper and lower leg portions together to prevent any further movement.
While various types of lock assemblies exist for securing the leg portions together, they typically include elements that either clamp the leg portions together using a substantially horizontally exerted force, physically engage an opening in one of the leg portions, or both. The lock assembly may be actuated by a knob or a lever disposed substantially adjacent the lock assembly itself. Alternately, in single stage tripods, the legs may be remotely actuated. This allows the user to readily adjust the leg locks while stabilizing the tripod head. For example, in U.S. Pat. No. 4,840,338 to O'Connor, the lock assembly secured to the lower end of the upper leg portion of a single stage tripod is actuated by means of a cable which runs from the lock assembly to the head of the tripod. An upward actuating force is exerted on the cable by means of either a rotating ring or collar, or an actuating lever which force is further transmitted onward to the lock assembly. This remote actuation is possible because the relative distance between the upper end of the tripod leg and the lock mechanism secured to the lower end of the upper portion of the leg remains constant even during-telescoping movement.
With a dual stage tripod, however, the distance between the lower lock assembly (which couples the middle and lower leg portions) and the upper end of the tripod leg does not remain substantially constant. Rather, as the upper and middle leg portions telescope, the distance between the lower lock assembly and the upper end of the leg necessarily changes. Accordingly, prior art methods of remote activation may not be used with the lower locks of a dual stage tripod. As a result, dual stage tripods are not so readily utilized or quickly set up because the user must stabilize the tripod head in a desired position while reaching down to secure each of the locks of each of the legs.
OBJECTS OF THE INVENTION
It is a primary object of the invention to provide a tripod which is easy to use and is fully adjustable from the head thereof. A more particular object is to provide a dual stage tripod with adjustable length legs wherein leg length adjustment can be made while an operator is gripping and controlling the tripod head with an instrument attached.
An additional object is to provide a dual stage tripod wherein the user may adjust any or all of the leg locks from the head of the tripod. A more particular object of the invention is to provide a dual stage leg wherein the lower lock assembly which secures the middle and lower leg portions may be adjusted from the upper end of the leg.
Another object of the invention is to provide a dual stage tripod wherein the lower lock of each of the legs may be actuated simultaneously. A related object is to provide a dual stage tripod wherein the lower lock of each of the legs may be actuated individually.
A further object of the invention is to provide a dual stage tripod wherein the upper lock of each of the legs may likewise be actuated simultaneously or the upper lock of a select leg may be actuated individually.
BRIEF SUMMARY OF THE INVENTION
In accomplishing these and other objects of the invention, there is provided a dual stage tripod wherein the lock assemblies of each of the legs may be operated from the tripod head. More specifically, the tripod includes a dual stage leg having means for actuating the lower lock from the upper end of the leg.
As with conventional dual stage legs, the leg includes upper, middle and lower leg portions, and upper and lower lock assemblies for coupling the upper and middle leg portions together, and the middle and lower leg portions together, respectively. A dual stage leg constructed in accordance with teachings of the invention further includes a torque shaft which extends from the upper end of the leg to a transfer assembly disposed at the upper end of the middle leg portion. The transfer assembly slides longitudinally along the torque shaft as the upper and middle leg portions telescope relative to one another. Rotation of the torque shaft about its longitudinal axis actuates the transfer assembly to result in a lower lock actuating force. This force is then transmitted from the upper end of the middle leg portion to the lower lock assembly disposed at the lower end of the middle leg portion to actuate the lower lock assembly. Accordingly, the user may actuate the lower lock assembly to couple or uncouple the lower lock assembly by rotating the torque shaft at the upper end of the leg.
According to another feature of invention, the user may actuate the lower lock assembly of each leg individually, or actuate the lower lock of each leg simultaneously. To actuate the lower lock assembly of an individual leg, the user may preferably directly rotate an associated torque shaft by pivoting a crank coupled to the upper end of the torque shaft.
Alternately, the user may rotate the torque shaft of each of the legs by means of a lower lock ring disposed subjacent the head of the tripod. The lower lock ring is coupled to the crank of each of the legs by means of a flexible cable or the like, such that when the user rotates the ring, the ring exerts a force on the individual cables to pivot the crank and rotate the torque shaft associated with each individual leg. In this way, the rotation of the lower lock ring actuates the lower lock assembly of each leg substantially simultaneously.
Accordingly to yet another feature of the invention, the user may likewise actuate the upper lock assemblies either individually or substantially simultaneously. The upper lock assembly is preferably coupled to the lower end of the upper leg portion and slidingly receives the middle leg portion. The upper lock assembly preferably is actuated by a cable which extends from a bell crank disposed at the upper end of the leg to the lock assembly disposed at the lower end of the upper leg portion. Accordingly, pivoting of the bell crank exerts an upward actuating force on the cable.
The upper lock assembly of an individual leg may be actuated by pivoting the bell crank of an individual leg. Alternately, the bell crank of each leg may be pivoted simultaneously by means of an upper lock ring to actuate the upper lock assembly of each leg substantially simultaneously. As with the lower lock ring, the upper lock ring is disposed subjacent the tripod head and preferably is coupled to the bell crank of each individual leg by means of cables. Accordingly, by rotating the upper lock ring, the user pivots the bell crank of each individual leg to actuate the upper lock assembly of each of the legs substantially simultaneously. Moreover, by rotating both the upper and lower lock rings concurrently, the user may actuate all of the lock mechanisms of the tripod substantially simultaneously.
In this way, durin
Autocue, Inc.
Braun Leslie A.
Leydig , Voit & Mayer, Ltd.
Marsh Steven
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