......building a prop bed for a production. My immediate problem is that the bed has to have a collapsing
leg. .......man throws his wife onto the bed......one of the legs breaks......bed tilts, and her petticoat
flies ......guffaw........The
bit needs to be repeatable through tech and 2 months of 8 performances a week....... the
leg can't fall a huge distance.......
OK, let's take a look at this. What are the parameters that define what we need to do?
1.
Leg "breaks" and bed tilts/falls.
2.
Gag must repeat, reliably, roughly 80/90 times.
3. Talent must not be injured.
4. Fall/tilt distance must be minimal to insure item #3.
Item 4 is the easiest. You don't say what the show is or the period and locale which could affect the bed design in terms of size and height. The bed design will have a strong
effect on the "fall Distance". To simulate a mattress and a bed, there will be a
thickness to the "box" section. That and the "normal bed height of about 20"-24" limits the
leg length to between 6" to 10". If your bed is a period piece that is higher, you can still limit the fall by designing the "break" to leave a stump or upper
leg section intact, that in reality or in illusion, prevents the bed from falling or tipping further.
3. As the "break" happens at the head of the bed, care must be taken to insure that any head board or bed posts are structurally attached and there are no sharp edges or corners. Pillows or other bedding might need to be firmly attached to insure it remains in place and acts as "fall padding" or conceals real padding as needed. Actor training and fight/fall training as well as
gag choreography are a must to insure performer
safety.
1 & 2.
Leg breaks! What happens when the
leg breaks? The bed, if unevenly loaded and heavy on the break side will pivot around the points where the two opposite corner legs contact the
deck and the corner opposite the "broken"
leg will rise up. The bed and whatever "load" is still on it are now supported by the opposite corner legs and at an angle and by whatever part of the bed is supported by the "gimmick " rigging at the break corner. So, step one is to
build and/or reenforce the two diagonal legs so they can handle the repeated stress of sudden angular,
shock loading. Real bed construction and "normal" shop construction techniques, especially using wood, are not what is called for. In my mind a welded steel frame would seem to be a wise choice if you have the shop and equipment to create it. I would also consider attaching the two pivot legs to the
deck with hinges aligned with the fall direction.
To make the
leg fall requires a pulling action. Whether it is a locking pin that is pulled or a hinged
leg that is pulled or something else, the mechanism (or string to
stagehand or whatever) has to work under the bed, so there is very little room for a "push" mechanism. There are probably a hundred ways to collapse the
leg, I will suggest just one possibility. I would think of a three part
leg. The first part is the stationary upper part that is permanently part of the bed frame. How far it protrudes below the main frame will determine the maximum fall distance. The under side of the first part is beveled 2-5 degrees away from the fall direction. The second section is hinged to the top with the
barrel on the same side that the "pull" is from. The top of the second section is also beveled just slightly 2-3 degrees so that it bends away from the direction of the "pull"
cord. The bottom of the 2nd section is also beveled just slightly the same direction so that the top and bottom are parallel. The bottom section is hinged to the middle section with the
barrel on the side opposite the "pull". The top of the lower section is beveled slightly toward the pull side. The bottom of the bottom
leg should be slightly rounded on the corner so that when it is pulled, it does not have to cam over a corner. Correctly beveled and hinged, the
leg will have a very slight
bend away from the pull direction and in
effect, cam over and become self locking under load. Depending on what the action on the bed is prior to the gimmick, you may or may not need to employ a secondary support or lock to prevent an unwanted collapse. You might want to install small springs or strong rubber bands on the sides to prevent a
leg collapse in the case of vibration or action on the bed that would put the
leg in a slight lifted or "no-load" condition. The
pull string/cable is attached to the
leg opposite the lower hinge. It may be activated by a
stagehand pulling a cable, a small motor and a
winch drum, a pneumatic or hydraulic cylinder,
etc. The string will need to be pulled the same distance as the the
thickness of the
leg, counting the
center line of the two hinge barrels as the
thickness. The trade off here is, the narrower the
leg, the less force and less distance the pull will require. The thicker the
leg, the more stable it will be before the
gag. The pull mechanism, if mechanical, can be built in or attached to the under side of the bed, requiring only signal wires to be connected. Stagehands usually object to being attached to scenery or
props, so that is out.
To dampen or not to dampen and if so how much. I am sure that the fall of the bed will not be sufficient to cause the petticoat to "
flies over her head" and will require some help and planning from the actress and choreographer. There will have to be a number of trials in the shop, long before tech rehearsals to determine what damping is needed and what performer actions are needed to carry off the
gag. At the same time it might be enough to require a little damping at the end. It may be as simple as piling some blankets and bedding under the bed that compress during the last couple of inches, it might be enough to warrant a gas
shock attached to the opposite corner to slowdown the rise of that part of the bed, like a gas
shock that slows down your hatchback as it rises up. If strong damping is called for, I do suggest the gas
shock on the opposite corner. Less of a problem of the
leg mechanism and the
shock absorber interfering with each other.
Anyway, this is just one of many ways that might work. More important, plan for R&D time in the shop, plan to get the director, performers and choreographer in the shop early to test and try. This is not something that should be designed, built and finished in the shop and presented Fait Accompli on
stage. Even if everything you do is perfect and 100% correct, to not involve the other players in the game up front, will be a major error in communications and professional relationships.
Anyway, hope this helps a
bit. BTW, What's the show?????
