Clamp for tripod device

A clamping component for a camera tripod top, said component comprising:- a clamping member, handle means for locking the component to said top, and means connected to and between said clamping member and said handle means permitting relative rotational movement there between, said handle means being adapted for threaded engagement with means connected to an opposing clamping member.

The present invention relates to tripods for cameras and more particularly, 
but not exclusively, to a clamping assembly for a ball levelling tripod 
top. 
In one conventional tripod, the legs of the tripod are pivotally attached 
to a body member or tripod leg mounting and a tripod platform is in turn 
attached to the body member. In order to permit levelling of the platform, 
the underside of the platform is hemispherical in shape and locates in a 
correspondingly hemispherical socket in the upper portion of the tripod 
leg mounting. The platform is secured in position by means of a clamp 
which bears on the underside surface of the tripod leg mounting. A clamp 
wing nut or hand wheel is provided to release or lock the clamp. To detach 
the platform from the tripod leg mounting, the clamp wing nut is removed 
and the clamp and its associated thrust washers come away under their own 
weight. In use the clamp and associated washers are often dropped during 
dismantling of the tripod and thus the conventional clamping device is 
inconvenient to use. 
It is an object of the present invention to provide a clamping device which 
is substantially free of the above disadvantages. 
The present invention in one general form is a clamping component for a 
camera tripod top, said component comprising: a clamping member, handle 
means for locking the component to said top, and means connected to and 
between said clamping member and said handle means permitting relative 
rotational movememt therebetween, said handle means being adapted for 
threaded engagement with means connected to an opposing clamping member.

In FIG. 1 there is shown a ball levelling tripod top to which at least 
three legs (not shown) are pivotally attached. The tripod top includes a 
body member 10 having on its upper side a hemispherical socket or a 
substantially concave surface 14 and on its under side a hemispherical 
convex surface 22. The body member 10 is provided with mounting brackets 
11 to which each tripod leg is pivotally connected. A mounting platform 
12, having a mating hemispherical convex under-surface or ball-seating 15, 
locates in socket 14 of the body member 10. Preferably a camera tilt and 
panning head 13 is secured to platform 12 by means of clamp bolt 16 which 
is provided with a threaded portion 18 on a reduced diameter section of 
the bolt. The threaded portion 18 of the bolt is screwed into a mating 
threaded bore 40 in the base of the tilt and panning head 13 to bring 
shoulder 45 of the bolt into contact with washer 17 and to attach the 
platform securely to the base of head 13. Tightening of screw 18 in bore 
40 is achieved by use of a bar or the like placed in eye 19 which is 
formed in the shank of the bolt. 
Platform 12 and the tilt and panning head attached thereto may be tilted in 
any transverse direction to level the platform in its body member 10. Once 
the platform is level it is locked into position by clamping member 20 and 
hand wheel or wing nut 23. The hand wheel 23 is formed with a female 
threaded portion 24 which engages a mating male threaded portion 25 formed 
on clamp bolt 16 at an end thereof remote from the tilt and panning head 
13. Clamping member 20 is annular in configuration having a hemispherical 
concave clamping face 21, which is located adjacent to and mates with 
surface 22 on the under-side of the tripod body member 10, a flat radial 
surface 41, and a bore 33 between surfaces 22 and 41 of the clamping 
member. A thrust washer 29 of fibre or any other suitable material is 
located about bolt 16 and between surface 41 of clamping member 20 and 
contact surface 42 of hand wheel 23. Accordingly, by screwing hand wheel 
23 on bolt 16 towards the tilt and panning head 13, body member 10 is 
gripped between platform 12 and clamping member 20 to lock the assembly. 
The clamping member 20 and hand wheel 23 are rotatably connected together 
by tubular sleeve 26. One end of the sleeve is provided with a retaining 
flange 27, which locates in recess 43 in clamping member 20. The other end 
of the sleeve is secured in bore or socket 36 in hand wheel 23. 
Sleeve 26 may be formed in a number of ways. The sleeve can be fabricated 
of aluminium and knurled along that portion 28 of the sleeve which locates 
in bore 44. Thus to assemble the clamp hand wheel 23 and clamping member 
20, sleeve 26 is placed in bore 33 of member 20, washer 29 is then located 
on the exposed portion of sleeve 26 and knurled portion 28 of the sleeve 
26 is finally pressed into socket 36 in hand wheel 23. To assist retention 
of the sleeve 26 in socket 36 an anaerobic resin adhesive may be applied 
to the knurled sleeve prior to the pressing operation. 
A simpler method of construction would be to fasten an aluminium tube with 
adhesive direct into socket 36. The protuberant part of the tube may then 
be passed through washer 29 and bore 33 and the end of the tube 
subsequently deformed to form retaining flange 27. Further the sleeve may 
be first fabricated in plastics material and subsequently affixed with a 
suitable adhesive onto socket 36. The sleeve does not require any great 
mechanical strength but only sufficient to rotatably hold hand wheel 23 
and clamping member 20 together. 
In yet another alternative the sleeve 26 may be integrally formed with the 
hand wheel as illustrated in FIG. 2. To permit assembly of the hand wheel 
30 and clamp member 20, the retention flange 27 of FIG. 1 is replaced by a 
split ring 34 and groove 35 in the upper end part of spigot 32. Bore 44 is 
sized to receive bolt 16 with a clearance fit, the bore terminating in 
threaded portion 31 which is sized to engage mating threaded portion 25 on 
the bolt.