Magnetic keyboard

申请号 US49598174 申请日 1974-08-09 公开(公告)号 US3916360A 公开(公告)日 1975-10-28
申请人 SINGER CO; 发明人 PEDERSEN EGON A; ROLPH DONALD L;
摘要 A magnetic keyboard assembly including a key stem magnetically held in an unactuated position by the attraction of a magnet to a metallic mounting board and adapted to be reciprocated between an unactuated position and an actuated position where an electrically conductive rubber grommet engages a contact pad having spaced-apart contacts which become electrically connected upon engagement of the electrically conductive grommet. The grommet is characterized by a resilient outer ring spaced from a center portion by a resilient web with the outer rim engaging the contacts first so that the outer ring slidably engages the spaced contacts as the center portion moves toward engagement with the contact pad, thus providing not only good operator touch to the keyboard but also assuring clear electrical contact by the slidable rubbing action of the outer ring.
权利要求
1. A magnetic keyboard comprising: mounting means of magnetic material having an opening therein; a key assembly including a key stem reciprocably mounted in said opening and a key top mounted at one end of said stem, said key assembly adapted to be reciprocated between a non-actuated position and an actuated position; magnetic means on said key stem and located on the opposite side of said mounting means from said key top; spacer means positioned between said mounting means and said magnetic means for providing a predetermined maximum holding force therebetween when said key is in said non-actuated position; a base member spaced from said mounting member and having an opening adapted to slidably receive one end of said key stem; a contact pad with spaced-apart contact means located on the side of said base member facing said spacer means; resilient electrically conductive means mounted on said key stem between said magnetic means and said base member and engageable with said spaced-apart contact means when said key is in its actuated position to electrically connect said spaced-apart contact means; said resilient electrically conductive means comprising a grommet having a first means for contacting said spaced-apart contact means upon initial engagement therewith to electrically connect said spaced-apart contact means, and a second means for engaging the contact pad, the bottom portion of which is spaced further from said contact pad than said first means when said key assembly is in the non-actuated position and thus only engages said contact pad upon further movement of said key after initial contact by said first means.
2. The magnetic keyboard as claimed in claim 1 wherein said first means of said grommet is so constructed and arranged to rub said spaced-apart contact means as said second means engages said contact pad upon further movement of said key so as to continually clean said contact means for continued enhancement of electrical conduction between said grommet and said contact means.
3. The magnetic keyboard as claimed in claim 2 wherein said first means of said grommet comprises an outer ring and said second means of said grommet comprises a center portion, said outer ring and center portion being separated by a resilient web, said center portion when engaging said contact pad taking the entire force of operator pressure on the key thus lessening possible damage to the contact means.
4. The magnetic keyboard as claimed in claim 3 wherein said outer ring slidably engages said spaced-apart contact means.
5. The magnetic keyboard as claimed in claim 4 in which said contact pad comprises a pair of concentric rings with interadjacent ears providing an interstitial non-conductive gap therebetween, which gap is bridged by said resilient electrically conductive means upon engagement with said pad.
6. In a magnetic keyboard assembly including a key stem magnetically held in a non-actuated position, an electrically conductive rubber grommet mounted on said key stem for electrically connecting spaced-apart contacts of a contact pad in said assembly when engaged by said grommet upon depression of said key with sufficient force to overcome the magnetic force holding said key in said non-actuatable position, said grommet having a first ring means for first contacting said spaced-apart contacts upon initial engagement therewith and a center portion for further engaging said contact pad upon further depression of said key, said ring and said center portion being separated by a resilient web.
7. The grommet as claimed in claim 6 wherein said outer ring slidably engages said spaced-apart contacts as said center portion moves toward engagement with said contact pad.
8. A magnetic keyboard comprising: mounting means of magnetic Material having an opening therein; a key assembly including a key stem reciprocably mounted in said opening and a key top mounted at one end of said stem, said key assembly adapted to be reciprocated between a non-actuated position and an actuated position; magnetic means on said key stem and located on the opposite side of said mounting means from said key top; spacer means positioned between said mounting means and said magnetic means for providing a predetermined maximum holding force therebetween when said key is in said non-actuated position; a base member spaced from said mounting member and having an opening adapted to slidably receive one end of said key stem; a contact pad with spaced-apart contact means located on the side of said base member facing said spacer means; resilient electrically conductive means mounted on said key stem between said magnetic means and said base member and engageable with said spaced-apart contact means when said key is in its actuated position to electrically connect said spaced-apart contact means; said resilient electrically conductive means comprising; a grommet having an outer ring and a center portion separated by a resilient web, the surface of said ring facing said contact pad being closer to said contact pad than the surface of said center portion facing said contact pad so that said outer ring first slidably engages said spaced apart contact means as said center portion moves toward engagement with said contact pad, the reaction force of said ring initially engaging said contact means being transmitted through said resilient web to said key stem and key top to provide the first step of a two-step touch to an operator, and engagement of said center portion with said contact pad, and to provide the second step and stop touch to the operator, said engagement of said center portion being directed to said key top independently of said resilient web whereby continued pressure by the operator on said key top is not transmitted to said ring, thereby eliminating possible damage to said spaced apart contact means by such continued pressure of the operator.
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