Get a Grip

Laura Woodward, Andy Paterson, Sal Cacciato and Brian Lee Huynh in Triad Stage’s The 39 Steps, with the working curtain gag.

One props master had to think outside the solenoid to get the window shade gag in The 39 Steps to work

Hannay is feeling a little tense. There’s a woman in danger, and two thugs lurking outside. In order to get some privacy, he pulls a window blind down. It rolls back up. He yanks it down again, but it rolls up again. He lowers it slowly, and this time it stays down. As he walks away, it suddenly snaps back up again. This is one of the many gags in 39 Steps, a humorous homage to Hitchcock films. When Triad Stage produced the show in the fall of 2014 it fell to me to make this gag work. 

For this production, the window with the blinds was a simple rolling unit, moved on and offstage rapidly during scene changes. This meant the trick needed to be self-contained (nowhere to conceal a crew member) and remote-controlled (we couldn’t have wires running backstage from the unit). 

Other props masters who have previously done this show have solved the problem with solenoids. If you disengage the brake on the blinds, they will always snap back up after they are pulled down. The third time the actor pulls them down, he slips the ring on the end of the string to a pin which sticks out of the window frame; this holds the blinds in the down position. The solenoid pulls the pin into the frame, releasing the string and sending the blinds back up into their roll.

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When I prototyped this solution, I found that the solenoid pin would bind up if it was being pulled too hard vertically; the pin was only meant to move in and out. The window shade was pulling on the pin so hard that the solenoid could not move it in when triggered. I had a window but no gag. I ordered a stronger solenoid, but it still did not work. Our AC solenoids used by scenery were strong enough, but we could not run a power cord out to the window unit.

Rather than trying to make the solenoid do all the work, I needed the solenoid to trigger something else. A pair of vise grips provided inspiration. The jaws stay closed, but because of the spring in the handle, a little squeeze can pop them open. I opened the jaws slightly, so a string could slip through, but a washer tied to the string could not. The jaws were perpendicular to the string, so you can pull up on the string as hard as possible, and they would not open. But a little sideways tug on the handle would open them with no problem. 

I built a little self-contained unit containing the vise grips, the solenoid, battery pack and a remote control device. Seán McArdle pointed me to a cheap but reliable two-channel RF transmitter and receiver unit he uses (which he discovered from Doc Manning) from Carl’s Electronics. This unit could attach and detach from the back of the window, with the jaws of the vise grip poking through a hole out the front just enough for the actor to get the string into. I added wood blocks to limit the movement of the solenoid pin, making it simple for the crew to reset it. It worked consistently throughout the run with the batteries only needing to be changed once.