Wanted: Simple Reverse Tension Spring Cylinder

If you have access to a set of Thomas Register books, there are probably twenty pages of manufacturers listed. Start calling until you find one that will work with you.

You have to understand that whenever there is an application for a spring, in most cases, the requirements are specific to the device. Spring manufactures can't stock binsful of all of every variation on spec, only the most common ones. Yes, your style is one of their designs but in order to produce it on demand requires a fair amount of set-up time. Unless you are prepared to pay a high price for a few units, I have found that sometimes a request for "samples" through the marketing department or engineering, who sometimes have the ability to knock out a couple of units, gets the problem solved. I have ALWAYS been up front with them in that the future requirement will probably not be for large quantities, if at all. But at the same time, they are getting a "foot in the door" for your future needs. They know you will consider them first next time. I recall asking and receiving an assortment of special sealing washers for a steering rack drain plug of a car I was restoring. The sales rep at Parker, California plant, was really interested in how it worked out, with the fluid and pressures involved, since they were not designed with that envelope in mind. I made a friend I could call on, and did, for other applications.

Hello well I reckon,

Are the springs an addition to a machine you have, or for something you are building?

If it is for a machine you have, can you tell me the machine type and name, model etc? Or what you plan to make for which you need the springs please?

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The reverse tension cylinder will be used on a training fixture we currently have in use. We have 3 of theses units that were poorly designed and cheaply built. The company that built them has been no help in providing a perment solution to the problem. The reverse tension cylinder will work very well and probably last longer than the fixture will be used, assuming I can locate 3 units to use. If you have ever seen a door closer (like used on storm doors or screen doors found in a typical house), that is what the units I need look like but have a larger rod with a hole for mounting using a bolt thru the rod end, body end mounts the same way. The spring needs to have 45# - 50# of pull, nderstanding the spring will "stack" as the unit is extended to full stroke to a max of about 60#. If a single unit is used the stroke must be 20" - 24", or I can use 2 units together of 15" stroke length. Units I have seen on the net at different product pages of companies that manufacture this type unit meet all the specs and both lengths but we will not purchase 200 units. The training fixtures are used in adult training environment/facility and the budget is very small.

Hello well I reckon,

Can you tell me the name of the original maker? Just so as I can get an exact size etc of the unit you need.

And, just a thought, but you mention door closures. Could it be possible to use one of these to replace the springs you need?

bb

The original units are equipt with a cheap cable unit that works similar to a hose reel. The cable is on a spool that has a spring mechanisum, similar to the recoil starter on a lawnmower. The cable is pulled out of the reel and attached to the bottom of the unit and applies constant pressure in the upward direction (retracting). For the training exercise the trainees push the unit in a downward direction a given number of times, then move to the next exercise. The cable unit is very cheaply built, training unit design is poor allowing the cable to float and rub against the sides of the lower unit and the abrasion causes the cable to break. Redesigning the units or having them build again is out of the question at this point. The reverse tension cylinder will solve the problem, I just need a source for 3 units.

Thanks

Hello well I reckon,

Can you please tell me the name of the machine?

bb

It's a training fixture, not a machine. It is a custom designed and build.

The reverse tension spring cylinder I need should have a minium 20" of stroke (more stroke is acceptable), with a body diameter of not more than 28mm, and eyelet ends that will allow a 5/16" - 3/8" bolt to pass through for securing the unit to the fixture. Retension pressure needs to be 45-50 lbs.

Thanks

Hello well i reckon,

I appreciate all the reply info' post, can you tell me what you use the 'training fixture' for please?

bb

You might try Clippard they make pneumatic cylinders with spring retract. i have bought single units easily from their distributors

Don't know if the gas springs that lift SUV hatches will work for you, they may go the wrong way. They sure are strong, maybe you could re-arrange things to use them.

Thanks for the info Mike, tried that and it does go the wrong way. I finally found an overseas source for the three units we needed and the problem has been resolved and project is finished.