Combined Woodworker’s Push-Stick and Furniture Alarm Unit
British inventor David Bartram was granted a UK patent (GB2233932A) in 1989 for his "woodworker's push-stick and furniture alarm unit."
In its first possible use, as a push-stick, his invention allowed woodworkers to push pieces of wood through a table saw while keeping their hand safely away from the saw blade.
In its second possible use, as a furniture alarm, the stick could be attached in between the legs of a chair. If the occupant of the chair happened to lean backwards, raising the front legs of the chair off the ground, the furniture alarm would emit a "startling warning."
Bartram clearly was annoyed by people who leaned backwards in chairs. He wrote:
Of course, for his invention to function as a furniture alarm some kind of "gravity-orientated switch" would need to be incorporated into it. Based on his patent description, it's not clear if Bartram had ever gone to the trouble of doing this, but it seems that he didn't anticipate it would be a problem.
He didn't address the major limitation of his two-in-one invention: if you've got it attached to the legs of a chair it's not available to use as a push-stick, and vice versa, if it's in your workshop being used as a push-stick, it's not guarding a chair.
In its first possible use, as a push-stick, his invention allowed woodworkers to push pieces of wood through a table saw while keeping their hand safely away from the saw blade.
In its second possible use, as a furniture alarm, the stick could be attached in between the legs of a chair. If the occupant of the chair happened to lean backwards, raising the front legs of the chair off the ground, the furniture alarm would emit a "startling warning."
Bartram clearly was annoyed by people who leaned backwards in chairs. He wrote:
This strains, loosens and can ultimately destroy, the chair joints. Quite apart from the fact that the chairs were not intended for such use, the costs nowadays of stripping and repairing a chair whose joints have become loosened can be high.
Of course, for his invention to function as a furniture alarm some kind of "gravity-orientated switch" would need to be incorporated into it. Based on his patent description, it's not clear if Bartram had ever gone to the trouble of doing this, but it seems that he didn't anticipate it would be a problem.
He didn't address the major limitation of his two-in-one invention: if you've got it attached to the legs of a chair it's not available to use as a push-stick, and vice versa, if it's in your workshop being used as a push-stick, it's not guarding a chair.
Comments
"A waffle iron with a phone attached"
--Abraham Simpson
--Abraham Simpson
Posted by crc on 07/31/24 at 04:59 AM
1st grade teacher, Salem, Indiana circa 1958, used to tie us in our chairs to stop this annoying chair tipping behavior. If you tipped and fell you got a nice hit on the noggin. My mother never stopped teasing me about getting tied into my chair until about High School age.
Posted by J. Weckbacher on 07/31/24 at 06:33 AM
As a woodworker, I can't think of anything more useless than a push-stick with a guard. To be safe, you need to be able to see everything clearly. Such a guard, even if it was clear plastic, would obscure/distort the most critical area.
Also, when cutting strips, the push-stick has to fit between the blade and the fence. This is necessary because the blade is pushing in the direction opposite to the board's movement. This is a problem when the cut completes because you have this thin strip which the saw is trying to throw at you. I have push-sticks 1/8", 3/8", and 15/16" wide because I want the widest support I can get while still fitting between blade and fence.
Also, when cutting strips, the push-stick has to fit between the blade and the fence. This is necessary because the blade is pushing in the direction opposite to the board's movement. This is a problem when the cut completes because you have this thin strip which the saw is trying to throw at you. I have push-sticks 1/8", 3/8", and 15/16" wide because I want the widest support I can get while still fitting between blade and fence.
Posted by Phideaux on 07/31/24 at 01:30 PM
My grandfather was a carpenter. When we visited - which was often and happy - we were never allowed to tip back our chairs. *Except* on the ones he had made himself. He knew those were made properly, glued rather than screwed, and they would be able to take the strain.
Posted by Richard Bos on 08/04/24 at 02:31 AM
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Category: Furniture | Patents | 1980s