Hi Chessie,
Many options were explored for getting the backrest attached to the fork frame. One problem with welding pins on the pallet fork frame is that it would be a hazard; a protrusion. Also, this wouldn't be field installable. One of the primary requirements for the design was that everyone who has already bought a set of forks won't be left out of having a backrest. Actually, this was Rule #1.
An alternate design to the lynch pins consisted of using knurled knobs with integrated high strength threaded shafts for the top connections which would be screwed into threaded standoffs in place of the present unthreaded standoffs. This solution was abandoned due to A) higher cost, B) much less convenience, C) threaded fasteners can unscrew (major safety concern), and D) having to deal with the loose fasteners when the backrest is stored away.
The final design, using the cleats screwed on to the pallet fork frame, is far less intrusive than any other approach considered as each screw is relatively small. Due to the high quality of these screws, each one has a failure strength of around 2500-3000 lbs and there are 4 of them per cleat (16 screws altogether). Also, having the screws opposing at 90 deg angles means that while two of the screws are in tension, there are two others in shear at all times which provides exceptional design safety.
For anyone who would rather use threaded fasteners than lynch pins to attach the backrest frame to the cleats, it would be easy to replace the lynch pins with screws/nuts (locknuts would be encouraged). This would be a fine idea for anyone who thinks they will install the backrest and never remove it.
In my own little world, however, I need a backrest very rarely so if I ever buy one for myself, it would most likely sit aside most of the time. Thus, the lynch pins fill the bill.
Does this answer your questions? If not, feel free to keep trying. And thanks for asking your question here on the forum!
Many options were explored for getting the backrest attached to the fork frame. One problem with welding pins on the pallet fork frame is that it would be a hazard; a protrusion. Also, this wouldn't be field installable. One of the primary requirements for the design was that everyone who has already bought a set of forks won't be left out of having a backrest. Actually, this was Rule #1.
An alternate design to the lynch pins consisted of using knurled knobs with integrated high strength threaded shafts for the top connections which would be screwed into threaded standoffs in place of the present unthreaded standoffs. This solution was abandoned due to A) higher cost, B) much less convenience, C) threaded fasteners can unscrew (major safety concern), and D) having to deal with the loose fasteners when the backrest is stored away.
The final design, using the cleats screwed on to the pallet fork frame, is far less intrusive than any other approach considered as each screw is relatively small. Due to the high quality of these screws, each one has a failure strength of around 2500-3000 lbs and there are 4 of them per cleat (16 screws altogether). Also, having the screws opposing at 90 deg angles means that while two of the screws are in tension, there are two others in shear at all times which provides exceptional design safety.
For anyone who would rather use threaded fasteners than lynch pins to attach the backrest frame to the cleats, it would be easy to replace the lynch pins with screws/nuts (locknuts would be encouraged). This would be a fine idea for anyone who thinks they will install the backrest and never remove it.
In my own little world, however, I need a backrest very rarely so if I ever buy one for myself, it would most likely sit aside most of the time. Thus, the lynch pins fill the bill.
Does this answer your questions? If not, feel free to keep trying. And thanks for asking your question here on the forum!
