The Access Tripod

Project Brief

Design objective

The design objective is to produce a low-cost tripod for independent and professional use by wheelchair-users. It will encompass tripod and hand-held aspects of digital video camera use whilst allowing the user to retain full mobility. The resulting design will not really be a 'tripod' at all, but will replicate all the functions of a standard tripod with the additional benefit of being wheelchair-accessible.

The plan is not to design the 'definitive model', but to devise a base model which can be both replicated and adapted by individuals. The initial prototype will be made for a wheelchair user operating the tripod by hand and with standard levels of dexterity, strength and upper body mobility. It is to be constructed in such a way to allow for the design to be adapted to individual requirements.

Initial experimental work has been undertaken resulting in prototypes 1 and 2. The results show that the application of precision engineering and innovative thought will produce the desired result.

Design specification

The Access Tripod must:

1. Be usable with a range of popular mini-DV and DV-pro cameras.
2. Free the user's hands for mobility, instead of using them to hold the camera.
3. Permit easy access to both camera and wheelchair controls.
4. Be capable of being adapted to fix to a range of wheelchairs, both manual and powered.
5. Allow the user to clear any doorway with the unit fitted that the wheelchair will normally clear.
6. Enable good posture to be maintained by the user.
7. Not adversely affect the general good balance or manoeuvrability of the wheelchair.
8. Allow the user to secure the system to the wheelchair in under two minutes, not including the main anchor blocks and the camera.
9. Allow the user to exit the wheel chair in less than ten seconds, without the need to remove the system or camera. i.e. the system must swing away from a pivot point while still holding the camera secure. It should also be possible to have the pivot on the left or right of the wheel chair as a preference.
10. Allow for use of the camera's viewfinder or monitor.
11. Incorporate moving elements of pan, tilt and slide. Be extremely smooth with no apparent starting friction.
12. Allow each moving element to be locked independently, and when all are locked the camera must assume a rigid attitude.
13. Allow a reasonable amount of vertical, forward and rear adjustment to enable good ergonomic positioning of the camera.
14. Use clamps knobs and handles which are as grip-friendly as possible.
15. As far as possible, minimise the judder effects of terrain.
16. As light as possible yet rigid enough to provide the user with confidence.
17. Silent in all movements, so as not to interfere with the microphone.
18. As far as possible, use parts which are corrosion-resistant to allow indoor and outdoor use.
19. If possible, resemble `camera type` components, i.e. black finish, satins, chromes etc., in all manufactured parts.
20. As far as possible, incorporate easily purchased parts and be capable of replication by on-specialists.
21. As far as possible, be low-cost and comparable to the purchase cost of standard tripods on the market.
22. Allow for individuals to develop and adapt the design to their specific access or filmmaking needs. This initial design will be made for a wheelchair-user, with The Access Tripod operated by hand and with average levels of dexterity, strength and upper-body mobility.
23. Be easy to store and transport.
24. Incorporate a carrying bag or case at reasonable cost.

Schedule of work

Major components of the system

• Anchor blocks: These fit to either side of the wheel chair, usually to the tubular structure, and provide the mounting point for the uprights that would support the sliding camera mount. Experimentally they have been constructed from engineering plastic, but the preferred material would be aluminium for it's strength/weight ratio, and non-flex. They also need a more precise socket and clamping arrangement so taht the uprights can be quickly locked into position and released.
• Uprights: These support the sliding camera mount and for the time being are considered solid items with no damping system. Again constructed from aluminium for its strength/weight ratio, design and manufacture.
• End pieces: These are clamped to the ends of the uprights and have several functions: enable fore and aft positioning of the sliding camera mount, so that the user can find their best position for the camera; one end piece also serves as a clamp to enable tilt or non-tilt of the sliding camera mount; the other end piece serves as a support and pivot point for the sliding camera mount; also serves as a gate function allowing the user to swing the sliding camera mount quickly into position and lock it. These items require good precision engineering and should also be manufactured from aluminium, as there is considerable load on the clamp end when the sliding camera mount is un-hinged.
• Camera head: This is the most complex part of the system, with several functions, such as supporting the camera on a locking plate with it quick release lever action and providing a grip handle from which a range of movements can be locked and released. The actual function of the camera head would be a horizontal rotation of at least 180 degrees. Using the tilt control on one of the end pieces it must be possible when all controls are relaxed, to position the camera universally, with tilt, pan, and slide. The pan or rotational movement must be smooth, with no apparent starting friction. Experimental work has shown that the most reliable method of sliding the camera head is via a wheeled function, using precision ball races encased in plastic wheels. These would ride on a lightweight hollow (or solid) aluminium structure.
• Vibration damping: No work has been done on this element to date. However experimental work on prototypes has demonstrated its importance and enabled clues to how this may be approached. It may also require some lateral thinking.
• The assembly: All the parts mentioned above are interactive and must fit together as a working system. This will involve a trial and testing phase (below).

Documentation and dissemination

Plans for The Access Tripod will be made available via this website (not necessarily exclusively) to enable world-wide, free and non-copyright access to the designs. The design will assume no prior engineering knowledge. Potential users be able to download design drawings, material specifications, locations of purchased parts, manufacturing notes, diagrams, high quality photographic data and advice on seeking local engineering assistance.

Consultation

Built into the construction programme will be a consultation process to trial the prototype and feed into subsequent modifications.

Three wheelchair-using camera operators who have expressed an interest in using The Access Tripod in their work will be instructed in its use and then asked to film using it over a period of days. A questionnaire and discussion will feed into subsequent design developments.

A fourth wheelchair-using camera operator will also be selected to follow the tripod through the complete construction process. They will be asked to use the draft documentation to construct their own tripod. Their comments will be used to modify the tripod and documentation for subsequent users. This process will also be documented photographically for use on the website to encourage the 'ordinary user' in the viability of construction.

When the design is distributed on the website, a facility will be included for individuals to post their comments and modifications and these will be fed back to the designer and to other users.

• Introduction
• A Clear Demand
• Project Brief

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This page last modified: 07 Sep 2007