WO2000012370A1

WO2000012370A1 - Camera dolly leg locking assembly

Info

Publication number: WO2000012370A1
Application number: PCT/US1999/019122
Authority: WO
Inventors: Leonard T. Chapman
Original assignee: Chapman/Leonard Studio Equipment, Inc.
Priority date: 1998-08-31
Filing date: 1999-08-24
Publication date: 2000-03-09
Also published as: AU5685099A

Abstract

A camera dolly or pedestal has legs (20) pivotably attached to a chassis (10). The positions of the legs can be changed to vary the chassis or pedestal wheel base. A locking pin (32) on the chassis has a conically tapered end (54) which engages a conically tapered socket (52) on the leg (20). A spring (50) pushes the locking pin (32) into engagement with the socket (52). The leg position is changed by lifting a handle (38) attached to the pin, to withdraw the pin from the socket, thereby freeing the leg to pivot to a new position. The pin automatically re-engages another socket on the leg, to lock the leg into position.

Description

DESCRIPTION

CAMERA DOLLY LEG LOCKING ASSEMBLY

BACKGROUND OF THE INVENTION

The field of the invention is camera pedestals and dollies used in television and motion picture production.

In the production of television programs or motion pictures, it is often necessary to maneuver a camera into different filming positions. The required camera movement may include elevating and lowering the camera, as well as lateral and longitudinal movement between the camera and subject. Camera pedestals and dollies are used to support a camera and perform the desired camera movements.

Some camera pedestals and dollies, for example, as described in U.S. Patent Nos. 5,174,593, and 4,765,769, have legs which are pivotably attached to a chassis. The legs can be moved into different positions, to effectively change the wheel base of the dolly or pedestal, for different applications. For example, to provide a more stable wheel base, the legs may be positioned at 45° positions to the chassis. Alternatively, if the pedestal or dolly must move through a narrow opening, such as a doorway, to follow a filming sequence, the legs can be moved in to a 0° position, so that the legs do not protrude beyond the width of the dolly chassis.

While the need to change leg positions occurs less frequently than changes in other camera pedestal or dolly operating parameters (such as camera platform or arm elevation and orientation, steering mode, etc.) it is still important and advantageous for the camera dolly or pedestal design to allow for quick, reliable and simple procedures for changing leg positions.

Accordingly, it is an object of the invention to provide a camera dolly or pedestal having an improved system for changing leg positions. Other and further objects and advantages will appear hereinafter. STATEMENT OF THE INVENTION

To these ends, a camera dolly or pedestal includes a leg pivotably attached to a chassis. A lock pin assembly is provided for locking the leg into position relative to the chassis. The lock pin assembly can be released, to quickly and reliably pivot a leg into a desired position, relative to the chassis. Once the leg reaches the desired position, the lock pin assembly again locks the leg in place.

In a preferred embodiment, the lock pin assembly includes a lock pin having a conically tapered lower end, and a cap on the upper end. The tapered end of the lock pin preferably engages one of several tapered sockets. A spring urges the pin into engagement with a socket. The pin may be attached to the pivotable leg, with the sockets on the chassis, or vice versa.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, wherein the same reference number indicates the same element, through the several views:

Fig. 1 is a perspective view of a prior art camera dolly;

Fig. 2 A is a section view of prior art camera dolly leg joint and pin lock assembly;

Fig. 2B is an enlarged section view of a prior art camera dolly leg pin lock assembly;

Fig. 2C is a side view thereof;

Fig. 2D is a top view thereof;

Fig. 3 is a perspective view of a camera pedestal;

Fig. 4 is a section view of the leg joint thereof, attaching the leg to the chassis;

Fig. 5 is a side elevation view, in part section, of an alternate leg joint of the camera pedestal shown in Fig. 3 ; Fig. 6 is an enlarged section view of an improved pin lock assembly for use in the leg joints shown in Figs. 2A, 2B, 4 and 5, on a camera dolly or camera pedestal;

Fig. 7 is a partial side elevation view thereof; and

Fig. 8 is a plan view thereof.

DETAILED DESCRIPTION OF THE DRAWINGS

As shown in Fig. 1, a well known camera dolly (the Super Pee Wee Dolly distributed by Chapman/Leonard, North Hollywood, California, USA) has an arm 14 supported on a chassis 12 for holding a camera 16. Legs 20 are pivotably attached to the chassis 12 of the camera dolly 10 via leg joints 18. The lateral and longitudinal spacing of wheels 22 on the legs 20 can be changed by changing the position of the legs 20.

Referring to Fig. 2 A, the leg joint 18 of the camera dolly 10 shown in Fig. 1 preferably includes a king pin 24, and a trapezoidal king pin cap 26, as described in detail in U.S. Patent No. 4,765,769.

Referring to Figs. 2B, 2C and 2D, the pin lock assembly 30, as shown in Fig. 2A, and used on the camera dolly 10 shown in Fig. 1, includes a pin 32 having a cylindrical lower end 44 with a flat bottom, and a pin cap 38 at the top end of the pin 32. The pin 32 extends through a chassis bore 34 in the chassis 12, with the cylindrical lower end 44 extending into a leg bore 36 in the leg 20. The pin cap 38 has a bevel surface 40 to match and sit flush against the trapezoidal shaped king pin cap 26. A cap bolt 42 is positioned within a cap bore 43 in the pin cap 38. The lower end of the cap bolt is threaded into or otherwise attached to the chassis 12. A bushing or o-ring 46 within the cap bore 43 frictionally engages the cap bolt 42.

In use, with this known design, to change the angular position of the leg 20 on the chassis 12, the user grabs the pin cap 38 and pulls it up, thereby withdrawing the cylindrical end 44 of the pin 32 from the leg bore 36. As the cap 38 and pin 32 are pulled up, the o-ring 46 within the cap bore 43 slides up on the cap bolt 42. The cap bolt 42 is fixed to the chassis and does not move. The friction between the o-ring 46 and cap bolt 42 creates drag on the movement of the pin 32, thereby requiring additional upward force to lift the pin 32, and also tending to somewhat slow movement of the pin 32. However, the o-ring 46 has been useful in that once the pin 32 has been pulled up, the o-ring 46 holds the pin 32 in the up position, against the force of gravity, until the leg position is changed, and the pin 32 is forcibly pushed back down, to once again lock the leg 20 into a desired position. On the other hand, the user must push the cap 38 down, after the leg position change is made or the leg will not be locked into position, and the dolly will not track properly.

Perhaps a larger disadvantage of this known design is that, because the pin 32 has a straight cylindrical end, the leg bore must provide sufficient clearance around the pin to allow the pin to move into and out of the leg bore without binding, and without requiring perfect alignment. This requirement for clearance necessarily introduced play into the leg, so that even when locked, the leg can move slightly. Even though slight, this play can degrade the dolly rolling and steering performance, especially when the accumulated play of all four legs is accounted for. As the legs move out of position, the steering geometry degrades, as explained in detail in U.S. Patent No. 5,375,863.

Referring now to Figs. 6-8, in a new camera or pedestal leg pin lock assembly 55, the pin 32 has a conically tapered end 52, instead of a cylindrical end 44, as shown in Fig. 2D. In addition, the leg 20 is provided with radially spaced apart tapered sockets 54, adapted to receive the conically tapered end 52 of the pin 32. In addition, a compression spring 50 is located within the cap bore 43. The bottom end of the cap bolt 42 is threaded into a boss 47 on the chassis 12. The spring 50 is captured between the lower end of the cap bore 43, formed in the pin cap 38, and the head 58 of the cap bolt 42. The cap bolt is fixed to the chassis 12. Consequently, the spring 50 constantly pushes down on the bottom surface of the cap bore in the cap 38, so that the cap 38 thereby constantly urges the pin 32 downwardly, to engage the tapered end 52 into a socket 54.

The number and positions of the sockets will vary with the particular leg positions desired. Typically, sockets will be located to provide 1°, 10°, 44°, 85° and 179° front leg positions and 1°, 44°, and 85° rear leg positions. Additional intermediate positions may of course also be provided. In use, to change the position of the leg 20, the user lifts the pin cap 38 to disengage the tapered end 52 of the pin 32 from the socket 54. While the user must overcome the downward force of the spring, there is no drag force, such as with the design shown in Fig. 2B, resulting from use of the o-ring 46. As the pin cap 38 is pulled upwardly, a pin head clearance hole 60 in the top surface of the pin cap 38 moves up and over the head 58 of the cap bolt 42. As soon as the tapered end 52 clears the socket 54, the pin cap 38 can be released. The spring 50 drives the pin 32 downwardly, so that as the leg 20 is pivoted, and the next adjacent tapered socket 54 on the leg comes into alignment with the pin 32, the pin will automatically move downwardly to engage the socket, with the pin 32 then snapping into the down position to lock the leg 20.

Accordingly, the user need not exert constant downward force on the pin cap 38, while "hunting" for a socket 54. In addition, the leg will automatically be locked regardless of whether the user pushes the cap 38 down. As a result, a leg position change can be more easily accomplished by a single camera dolly operator. If necessary, the operator can use both hands to maneuver the leg 20, after the pin 32 is initially lifted out of the socket 54, and the leg slightly displaced, as once the socket 54 is displaced from alignment with the pin 32, no further downward force is required on the pin cap 38 to reengage the pin, to lock the leg 20 into position.

As the pin and socket are tapered, only a small amount of upward force is needed to cause them to disengage. As a result, the total upward force needed to disengage them, and to overcome the downward spring force, is nominal, in contrast to the force required to operate the design shown in Figs. 2A-2D.

As shown in Fig. 1, the leg 20 is attached below the chassis 12. Turning to Figs. 3 and 4, the leg is attached on top of the chassis. The lock pin assembly shown in Figs. 6-8 may be used on either design.

Fig. 5 shows an alternative embodiment for use in a camera dolly or pedestal having a leg 20 mounted on top of the chassis 12. In this embodiment, the spring 50 urges the pin 32 upwardly into engagement with a socket 54 on the leg 20.

Claims

WHAT IS CLAIMED IS:

1. A camera dolly or pedestal having a chassis, a leg pivotably attached to the chassis, and a lock pin assembly for locking the leg in position relative to the chassis, the lock pin assembly characterized by:

a lock pin having a first end and a tapered second end;

a pin cap attached to the first end;

a tapered socket on the leg adapted to receive the tapered second end of the pin; and

a spring linked to the lock pin and biasing the tapered second end of the pin into the tapered socket.

2. The camera dolly or pedestal of claim 1 wherein the pin cap has a beveled lower surface.

3. The camera dolly or pedestal of claims 1 or 2 further comprising a trapezoidal king pin cap adjacent to the lock pin assembly.

4. The camera dolly or pedestal of claims 1 or 2 further comprising a spring bore in the lock pin cap, with the spring contained in the spring bore.

5. The camera dolly or pedestal of claim 4 further comprising a cap guide bolt extending through the spring, and head on the cap guide bolt overlying the spring.

6. The camera dolly or pedestal of claim 5 wherein the cap guide bolt is attached to the chassis.

7. The camera dolly or pedestal of claim 1 wherein the tapered end of lock pin is tapered at from 5-15┬░.

8. The camera dolly or pedestal of claim 7 wherein the lock pin is tapered at 10┬░.

9. A camera dolly having a chassis, a leg pivotably attached to the chassis via a leg joint, having a kingpin, and a kingpin cap on the leg joint characterized by:

a lock pin adjacent and parallel to the kingpin, the lock pin having a first end adjacent to the kingpin cap, and a second end opposite the first end, the second end having a conical taper;

a pin cap attached to the first end of lock pin, the pin cap having spring bore;

a spring within the spring bore;

a cap guide bolt attached to the chassis and extending through the spring;

a retaining head on the cap guide bolt, retaining the spring in the spring bore; and a plurality of radially spaced apart sockets on the leg, with each socket having a conical recess adapted to receive the second end of the pin.