Universal tripod for supporting a camera or the like

Universal tripod comprises a tripod hub, tripod legs and clamping means for the legs. The legs are independently pivotally mounted on the hub and are each arcuately movable from a closed position, in which they are clustered around the tripod axis, to an extended position in which they may extend at an angle of up to about 120 degrees from the axis. The leg clamping means comprises a locking dog for each of the legs and a single clamping member which is movable between an unlocking and a locking position. When the clamping member is in its locking position, the legs are securely clamped against arcuate movement.

FIELD OF THE INVENTION 
This invention relates to tripods particularly of the type which have 
independently pivoted legs so that they can be used on irregular surfaces. 
BACKGROUND OF THE INVENTION 
A conventional tripod of the type used by photographers comprises a tripod 
hub and three legs pivoted to the hub and arcuately movable from closed 
positions to extended positions in which all of the legs extend at the 
same angle with the tripod axis, usually about 40 degrees. The legs are 
normally composed of two or three telescoping sections so that they can be 
lengthened at will. Conventional tripods of this type are satisfactory 
when used on a level surface in that the legs are merely moved to their 
extended positions and the tripod is positioned on the surface. If it is 
desired to raise the instrument being supported by the tripod, the 
extensions on the legs are pulled out by a uniform amount. When however a 
conventional tripod is used on an irregular surface such as the side of a 
bank or hill or on a rocky surface, the telescoping sections of the three 
legs must be extended to different lengths if the head of the tripod is to 
support the camera in a level position. This operation is time consuming 
and inconvenient for a photographer who requires the use of a tripod on an 
uneven terrain. Furthermore, a conventional tripod cannot be positioned on 
a surface such that the camera is relatively close to the surface; the 
minimum height is usually that height which is obtained when the camera is 
positioned on the surface with the leg sections fully telescoped into each 
other. 
The present invention is directed to the achievement of a universal tripod, 
which, with very little adjustment, can readily be set up on an irregular 
surface such as a sloping surface or a surface covered with rocks. The 
invention is further directed to the achievement of a tripod which can be 
set on a surface such that the head of the tripod, and therefore the 
camera or other device mounted on the head, is very close to the surface. 
This feature of the invention is of value to photographers engaged in 
photographing objects such as flowers or rock formations. 
A tripod in accordance with the invention comprises a tripod hub having 
three tripod legs independently pivoted thereto for arcuate movement 
between closed positions, in which the legs are clustered around the 
tripod axis, to extreme extended positions in which each of the legs 
extend at an angle of about 120 degrees with respect to the tripod axis. A 
leg clamping means is provided comprising a locking dog for each of the 
tripod legs and a locking member, or clamping member, movably mounted on 
the hub for movement between a locking position and an unlocking position. 
When the locking member is moved to its locking position, the individual 
locking dogs are simultaneously moved into engagement with their 
associated tripod legs thereby to lock the legs in the positions they 
occupy. Moreover, it is merely necessary in setting up the tripod to hold 
the tripod by the hub with the locking member in its unlocked position and 
lower the tripod towards the surface so that the legs are splayed 
outwardly as they come into contact with the surface. The locking member 
is then moved to its locking position and the legs will be rigidly and 
securely held against movement so that the tripod will set firmly on the 
surface.

Referring first to FIGS. 1-4, a tripod 2 in accordance with the invention 
comprises a hub assembly 4, three tripod legs 6 pivoted to the hub 
assembly, and a mounting means 8 on the hub assembly having a mounting for 
a camera or the like thereon. 
The hub assembly comprises a hub frame 10 having an upper surface 11, as 
viewed in the drawing, and a clamping means generally indicated at 12 
which is above the surface 11. The hub frame has three pairs of spaced 
apart ears 15 extending laterally therefrom at equally spaced angular 
intervals around the axis of the tripod, each pair of ears defining a 
recess 14 which receives a cylindrical gear-like member 16 on the end of 
one of the tripod legs 6. The gear-like member 16 is secured to the leg as 
shown in FIG. 2 by means of a plug 22, which is fitted into the hollow 
interior of the leg, and a pin 20 which extends into the plug and into a 
drilled hole in the member 16. The member 16 has serrations or teeth 18 
extending across its arcuate surface for engagement with complimentary 
teeth 34 on a locking dog 30 described below. 
The legs are pivotally mounted on the hub frame by means of pivot pins 26 
which extend through aligned holes 27 in the ears and through a central 
hole 24 in the member 16. The pin 26 has a threaded end as shown at 28 and 
one of the ears is also provided with a threaded hole to secure the pin 
after assembly of the parts. 
Each leg 6 has associated therewith a locking dog 30 which is positioned in 
the associated recess 14 and which has an upper surface 36 which is 
normally located above the level of the surface 11 of the hub frame 10. 
Dog 30 has an arcuate surface 32 on its outwardly facing side, the radius 
of which substaneially conforms to the radius of the gear-like member 16. 
Teeth or serrations 34 are provided on surface 32 for engagement with the 
teeth 18 on member 16 as described below. Each locking dog 30 is slidably 
positioned in a recess 14 for movement towards and away from the gear-like 
member 16 in the recess. 
An inclined surface 40 is provided at the inner end of the recess and a 
complimentary inclined surface 38 is provided on the locking dog 30 so 
that the dog will move radially towards the axis of the pin 24 as shown in 
FIGS. 2 and 3. 
The clamping means 12 comprises locking nut 42, a metallic washer 48, and a 
resilient gasket or clamping pad 50 located above the surface 11 of the 
hub frame. The locking nut 42 is threaded on the upper end 44 of a sleeve 
46 which is fitted in a central opening in the upper frame 10 and secured 
thereto by means, not shown, such as a key or a weldment. The metal washer 
48 and the circular resilient gasket or clamping pad 50 have oversized 
central openings so that they can move freely in an axial direction with 
respect to the upper end 44 of the sleeve. 
The locking nut 42 is in its unlocked position when it is backed off from 
the surface 11 as shown in FIG. 3 so that the legs can be moved arcuately. 
When the legs are moved, they will push the locking dogs upwardly to the 
position of FIG. 3. When the locking nut 42 is rotated to move downwardly 
to the position of FIG. 2, the locking dogs are simultaneously moved 
against the arcuate surfaces 28 of the members 16 to lock the legs in the 
positions they occupy at the time of engagement of the dogs with the legs. 
The camera mounting means 8 has a tube or neck portion 52 extending 
downwardly into the hollow interior of the sleeve 46. The neck 52 is held 
in the tube or sleeve 46 by means of a set screw 53 which is threaded 
through an opening in the hub frame 10 and which extends through an 
opening in the sleeve 46 to the neck 52. A plug 56 is fitted into the tube 
or neck 52 at the lower end thereof for purposes described below. 
In use, and after the camera or other instrument has been secured to the 
head 8, the hub frame 10 is held with one hand and the locking nut 42 is 
backed off to the position of FIG. 3 with the other hand thus freeing the 
legs for independent arcuate movement. The tripod is then positioned on a 
surface by simply moving the hub frame 10 downwardly so that the legs 6 
assume extended positions as required by the irregularities of the 
terrain. When all three legs touch the surface on which the tripod is 
being set up, the locking nut is rotated to cause its downward movement to 
the position of FIG. 2 thereby compressing the resilient member 50 and 
urging the locking dogs against the members 16. The user's hands can then 
be removed from the tripod since it will rest on the surface with a high 
degree of stability. 
When the tripod is set up on a level surface, all of the legs will of 
course assume the same angle with respect to the tripod axis as is the 
case with a conventional tripod. When the tripod is used on an highly 
irregular surface, one or more of the legs may extend at an angle in 
excess of 90 degrees with respect to the tripod axis as shown in FIG. 5. 
FIG. 5 also illustrates the fact that the tripod can be set up such that 
the camera is very close to the surface on which the tripod rests, a 
feature which is particularly advantageous when it is desired to 
photograph up close small objects such as insects or flowers. 
The individual legs 6 can consist of two or more telescoping sections if 
desired to permit the positioning of a camera in an elevated position. 
Also, means for raising the camera can be provided as shown in FIGS. 6 and 
7 in the form of a rod 66 having a reduced diameter threaded end 68. This 
rod is carried on one of the legs by means of a clamp 70 and a holding 
plate 72 when not in use. When it is desired to use the rod 66 to elevate 
the camera above the level normally achieved, the set screw 53 is loosened 
and the head is slid from sleeve 46. 
The threaded end 68 of the rod 66 is then screwed into a threaded opening 
54 in the plug 56 of the neck 52 of the head. Thereafter, the lower end of 
rod 66 is slid into the sleeve 46 and locked in position by the set screw 
53. 
The parts of the tripod described above can be made out of metal or in some 
cases suitable plastic. For example, the locking dogs 30 are preferably of 
a somewhat compressible plastic material so that they can be firmly 
engaged with the teeth 18 of the member 16 on the inner ends of the legs. 
If these members are of plastic as shown in the embodiment of FIGS. 1-4 
they will be moved out from the members 16 by the teeth 18 when the legs 
are moved outwardly from their closed positions. 
FIG. 8 shows an alternative form of locking dog 58 which may also be of a 
firm plastic and which is slidably contained in a recess which extends 
inwardly from the surface 11 towards the axis of the tripod pin 26. In 
this embodiment, a leaf spring 60 extends through, and is contained in, a 
traverse opening in the locking dog and has its projecting ends supported 
in the hub frame. This leaf spring normally biases the locking dog away 
from the gear-like member 16 and the dog is moved towards the gear-like 
member against the biasing force of the spring when the locking nut is 
moved to its locking position. 
FIG. 9 shows a locking dog 62 composed of two metal parts, one of which is 
recessed and the other of which has a projection extending into the 
recess. The two parts are held in assembled relationship to each other by 
a lost motion connection. A spring 64 is interposed between the parts and 
normally biasses them to their extended positions. When the locking nut 42 
is in its unlocked position as shown in FIG. 9, the end of the locking dog 
is resiliently biased against the teeth 18 of the member 16. The legs can 
thus be moved arcuately and a ratching effect will be achieved by the 
spring biased locking dog thereby to retard somewhat the movement of the 
legs without preventing it. It is unnecessary to provide the resilient 
clamping gasket 50 for the embodiments of FIGS. 8 and 9.