US3588766A - Arrangement,preferably for operating contacts for switching or control devices and the like - Google Patents

Abstract

CONTROL APPARATUS HAVING A PLURALITY OF PUSHBUTTONS WHICH MAY BE INDIVIDUALLY MOVED TO AN ACTUATED POSITION, HELD THERE BY MAGNETIC ATTRACTION AND SIMULTANEOUSLY RELEASED TO THE NONACTUATED POSITION. THE PUSHBUTTONS ARE HELD IN THE NONACTUATED POSITION BY MAGNETIC ATTRACTION TO A FIXED SUPPORTING MEMBER. THEY ARE HELD IN THE ACTUATED POSITION BY MAGNETIC ATTRACTION OF MAGNETIC POLES ASSOCIATED WITH THE PUSHBUTTONS FOR LIKE SPACED BUT OPPOSITE POLARITY MAGNETIC POLES ON A SECOND MEMBER WHICH IS MOVABLE TO A SECOND POSITION TO BRING MAGNETIC POLES OF LIKE POLARITY INTO OPPOSITION AND REPEL THE PUSHBUTTONS TO THE NONACTUATED POSITION.

Description

United States Patent 72] Inventor Max Baerrnann 506 Bensbcrg Bcdrk Cologne (Rhine), Germany Oct. 17, I969 June 28, 197i 211 Appl.No. 22 Filed [45} Patented 52 us. c1 335/207, 178/17, 235/145, 335/306, 340/365 [51] Int-CL I-I0lf7/04 [56] References Cited UNITED STATES PATENTS 3,129,302 4/l964 Postel... 0. 335/206 3,! 76,097 3/l965 Wood 335/205X Primary Examiner- Bernard A. Gilheany Assistant Examiner-R. N. Envall, Jr. Attorney Meyer, Tilberry and Body ABSTRACT: Control apparatus having a plurality of pushbuttons which may be individually moved to an actuated position, held there by magnetic attraction and simultaneously released to the nonactuated position. The pushbuttons are held in the nonactuated position by magnetic attraction to a fixed supporting member. They are held in the actuated position by magnetic attraction of magnetic poles associated with the pushbuttons for like spaced but opposite polarity magnetic poles on a second member which is movable to a second position to bring magnetic poles of like polarity into opposition and repel the pushbuttons to the nonactuated position.

[so FieldoISearch 335/205, 206, 207, 306; 340/365; 235/145; 178/17 (A), 17 0,101,110

Patented June 28, 1971 3,588,766

\E" m W/2. 1%: 38 24 2'4 52 38 I 24 IO '6 32A l-c.

FIG. 3

'NVEN'TOR MAX BAERMANN BY I Mew/MW a a ATTORNEYS ARRANGEMENT, PREFERABLY FOR OPERATING CONTACTS FOR SWITCHING OR CONTROL DEVICES AND THE LIKE This invention pertains to the control art, and more particularly to apparatus for holding and releasing a plurality of actuators for a control.

The invention is particularly applicable to an apparatus for holding operated the contacts of a plurality of electric switches or other devices, and simultaneously releasing the holding action, and will be described with specific reference thereto; however, it is to be appreciated that the invention has broader applications and may be used in a variety of devices which must be releasably controlled. I

Apparatus used for holding operated a plurality of switching or controlling devices has heretofore been equipped with either levers, mechanical locks, rollers or shafts provided with cams, or combinations thereof, for the purpose of releasably holding the actuators in an actuated position. Additionally,

. springs are usually provided for returning the individual actuators to their normal position. Thus, it can be readily seen that heretofore only mechanical means have been employed to effectuate the return to the nonoperated position operation.

The. principal problem with the mechanical means discussed above, is that they are subject to considerable wear and as 'i'such, failures frequently occur. Additionally, these mechanical means are often quite difficult and expensive to manufacture due to their complex design.

The present invention contemplates a new and improved apparatus which overcomes all of the above-referred problems and others, and provides a magnetic means for holding actuated actuators for switches or control devices which means is resistant to wear, may be easily and rapidly constructed, and is inexpensive to manufacture.

In accordance with the present invention there is provided a pair of elongated members in spaced parallel relationship, one of the members being fixed and the other of the members being movable in a plane parallel to the other and at least one actuator carried by the fixed member and including a permanent magnet portion with at least two poles of alternate magnetic polarity. The actuator is releasably held in one position by magnetic attraction to the fixed member and is displaceable toward and held in a second position by magnetic attraction to opposite magnetic poles on the movable member. The poles on the movable member and the actuator are of substantially equal pole pitch and so arranged that when the movable member is moved a pole pitch, the actuator is biased toward the fixed member by magnetic repelling action. The fixed member may either have opposite polarity-poles to attract the magnet portion or may be of ferromagnetic material such that poles on the magnet portion are attracted thereto.

in accordance with a more limited aspect of the present invention, magnetically actuated switches may be positioned so as to be actuated by the magnetic field of the magnet portion when it is in either position.

. Actuator as used herein is any member such as a push button, lever, rod or key which when moved from one position to another performs a control function such as closing or opening an electric switch, a valve or the like.

The principal object of the present invention is to provide an apparatus having a plurality of actuators, wherein all the actuators may be simultaneously released from an actuated position.

Another object of the present invention is to provide an improved apparatus having a plurality of actuators which is resistant to wear, thereby reducing the possibility of failure.

A further objectof the present invention is to provide an improved apparatus having a plurality of actuators which has a minimum number of moving parts and which may be rapidly and easily assembled.

A still further object of the present invention is to provide an improved apparatus having a plurality of actuators which is inexpensive to manufacture.

These and other objects and advantages will become apparent from the following description used to illustrate the preferred embodiments of the invention when read in connection with the accompanying drawings in which: I

FIG. 1 is a longitudinal cross-sectional view of apparatus having a plurality of actuators constructed in accordance with the preferred embodiment of the present invention;

FIG. 2 is an enlarged cross-sectional view taken along line 2-2 of FIG. 1; and

FIG. 3 is a longitudinal cross-sectional view of a modified arrangement of the apparatus of FIG. 1.

Referring nowto the drawings wherein the showings are for the purpose of illustrating preferred embodiments of the invention only and not for the purpose of limiting same, FIG. 1 illustrates the application of the present invention to a keyboard, such as commonly found on calculators. Although only a portion of the keyboard has been shown, it is to be appreciated that in such an application, keys from 0 to 9 would be provided. Furthermore, several rows of these keys can be arranged behind one another to form the complete keyboard.

The calculator shown includes a casing 10, in which are disposed a pair of spaced parallel elongated members 12, 14. Member 12 is secured to the casing 10 and hence remains stationary during the operation of the apparatus. Member 14 is movable within the casing 10 on a line of movement parallel to the fixed member 12. A plurality of guides 16 are secured to the fixed member 12 and extend downwardly therefrom toward the movable member 14.

In accordance with the present invention, there is provided actuators which may take a variety of forms; however, according to the preferred embodiment it takes the form of a key, designated generally by the reference numeral 18. The key 18 includes a button 20, a stem 22 extending outward from the key button and a permanent magnet portion 24 secured to the bottom of the stem. The stem 22 passes through an opening 30 in the fixed member 12, whereby the button 20 is positioned outside of the casing 10 for easy access by the operator of the calculator and the permanent magnet portion 24 is located beneath the fixed member 12 and hence inside the casing. The key 18 is displaceable toward the movable member 14, in a direction which is generally perpendicular to the direction of movement of the movable member 14. The permanent magnet portion 24 is so magnetized, that on an upper surface 32 it has, moving from left to right, a south pole and a north pole, and on a lower surface 34 it has, moving from left to right, a north pole and a south pole. it is to be appreciated that any number of keys 18 may be employed, depending upon the particular use to which the subject invention is put. However, for purposes of illustration, only five such keys have been shown.

The fixed member 12 may be of magnetically permeable material, or as shown, of magnetizable material, magnetized with alternating poles, which are designated by the letters N and S and which are opposite in polarity to the poles on the upper surface 32. The movable member 14 has a plurality of magnetic poles designated by the letters N and S which in the normal position shown in FIG. 1 are of opposite polarity to those on the lower surface 34. All of the poles have the same pole pitch, as diagrammatically represented by the dimension d. With this arrangement the keys are held in the vertically up position by the magnetic attraction of the poles on the upper surface 32 for the fixed member 12. However, if sufficient pressure is exerted on the key button 20 this magnetic attraction is overcome and the button moves downwardly guided by stem 22 until the lower surface 34 comes into proximity with the movable member 14. At this point the magnetic attraction of the poles pulls the surface 34 into engagement with member 14 and the key button 20 is then magnetically latched in this position.

In accordance with the invention member 14 is displaceable from a normal first position shown in FIG. 1 to a second position, as shown in dashed lines in FIG. 1 the distance between said positions being equal to approximately one pole pitch, as indicated by the dimension d whereby the poles on member 14 oppose like poles on surface 34. A repelling action results which biases the key button 20 upwardly to where the magnetic attraction of the poles on surface 32 for member 12 is restored and the key button remains in this position. The member 14 is biased to the first position shown in FIG. 1 by biasing means which may take a variety of fonns; however, in the embodiment shown it takes the form of a compression spring 36. One end of the spring 36 is secured to one end of the movable member 14 and the other end of the spring is secured to a support member 38, which preferably is connected to the casing 10. Secured to the other end of the movable member 14 is a cancelling button, designated generally by the reference numeral 40. The cancelling button 40 includes a key portion 42 which is located outside of the casing where it is readily accessible to the operator and a stern portion 44 which extends outward from the key portion, passes through an opening 46 in the casing and is connected to the end of the movable member 14. Depressing the cancelling button 40 will displace the movable magnet member 14 from its normal first position to the second position. Upon releasing the cancelling button 40, the spring 36 will return the movable member 14 from the second position to the first position. The direction of displacement is indicated by arrows.

It will be seen that the poles on the fixed member 12 and permanent magnet portion 24 are so arranged, that the poles on the fixed magnet member are always facing unlike poles on the upper surface 32 of the pennanent magnet portion. As.

such, the keys 18 are normally held in an uppermost position due to the magnetic attraction between the fixed magnet member 12 and the permanent magnet portion 24. When the movable member 14 is in the normal first position, the poles on the lower surface 34 of the permanent magnet portion 24 face unlike poles on the movable magnet member. Depression of a desired key 18 or combination of keys, will cause them to travel downward until they reach the movable magnet member 14. The keys 18 will be retained in this selected downward position due to the magnetic attraction between the poles of permanent magnet portion 24 and the movable member 14. This magnetic retention force is greater than the attracting force existing between the permanent magnet portion and the fixed member 12, due to the proximity of the permanent magnet portion to the movable member.

In order to simultaneously switch off the device and thereby return all of the depressed keys 18 to their normal uppermost position, it is only necessary to actuate the cancelling button 40. By pressing the button 40, the movable member 14 is displaced from the normal first position to the second position, the distance between said positions being equal to one pole pitch as represented by the dimension d. A stop piece 52 is provided to assure that the amount of displacement is limited to one pole pitch. When the movable member 14 is in the second position, the polarity with respect to the depressed keys 18 (the first and third keys as viewed from the right-hand side in FIG. 1) is reversed, that is, the poles on the lower surface 34 of the permanent magnet portion 24 are now facing like poles on the movable member 14. This causes the keys 18 which are depressed to be repelled by the movable member 14 and displaced in an upward direction. During the upward displacement of the keys 18 they come within the magnetic field of the fixed member 12 and are attracted to it and held in their normal uppermost position due to the opposing unlike poles on the upper surface 32 of the permanent magnet portion 24 and the fixed member 12. It is to be particularly noted that in view of the novel arrangement of the subject invention, all of the depressed contact keys 18 are simultaneously switched off and returned to their normal position. The spring 36 returns the movable member 14 from the second to the first position and selected contact keys 18 may once again be depressed.

The key buttons may of course be mechanically or magnetically associated with any device which it is desired to actuate. For example, in FIG. 2 the key buttons are shown as controlling'the operation of magnetically actuated reed switches, designated generally by the reference numeral 54. The reed switches 54 are arranged adjacent to the region where the permanent magnet portion 24 makes contact with the movable member 14 when the key 18 is depressed. Each reed switch 54 as is conventional may include a pair of magnetically responsive contacts 56, 58. When the key 18 is in its normal uppermost position, the contacts 56, 58 of the reed switch 54 are moved either to open or closed position as desired. In the embodiment shown the contacts are normally open as illustrated by the second key from the right in FIG. 2. However, when the key 18 is depressed, the contacts 56, 58 close in response to the magnetic field emanating from the permanent magnet portion 24 of the depressed key. It is to be appreciated that the contacts 56, 58 of the reed switch 54 can be connected to a variety of external devices (not illustrated) whose operation is to be controlled by the magnetic contact apparatus of the subject invention. It is to further be appreciated that although a dry reed switch has been illustrated, other devices could be employed which would be subject to the magnetic effect of a depressed key 18, such as a Hall generator. Also, reed switches can be disposed adjacent the uppermost position of the magnet portion 24.

A wide variety of permanent magnet material can be used to construct the members 12, 14 and the permanent magnet portion 24, provided it possesses sufficient coercive force. However, permanent magnet materials having a coercive force of more than 1000 Oersteds are preferred. Examples of such preferred materials are the barium, strontium or lead ferrites, which have the additional advantage of being relatively inexpensive. Although the magnet members 12, 14 could be manufactured in various ways, preferably they are constructed from powdered permanent magnet material bound into an integral body by means of a plastic which may be either flexible or rigid. Furthermore, by using such plastic bound permanent magnet material it is possible to employ injection molding, extrusion or pressing techniques to integrally form not only the contact key 18, but the members 12, 14 thereby reducing the overall cost of manufacture.

It is to be appreciated that the invention is not limited to a permanent magnet portion 24 having only a pair of alternating poles, as shown in FIG. 1. Thus, in order to achieve a higher attraction force, the permanent magnet portion 24 can be provided with several poles of alternating polarity, provided the pole pitch of such poles are the same as those of the members l2, l4.

It is further within the scope of the present invention to construct the magnet members l2, 14 from a plurality of individual smaller permanent magnets, each of which has been magnetized with two poles. These individual magnets can then be arranged on a ferromagnetic body concentrating the lines of magnetic force or on a nonmagnetic carrier plate. Furthermore, the permanent magnet portion 24 can be magnetized in the direction of its smallest dimension, its largest dimension or so that the lines of magnetic force are curved in its interior, all of which depends entirely upon the type of permanent magnet material used.

Reference is now made to FIG. 3, wherein a modified embodiment of the present invention is shown. This embodiment is substantially identical to the apparatus illustrated in FIG. 1, except that the fixed member 12 of permanent magnet material has now been replaced by a ferromagnetic member 60 of good magnetically conductive material. The contact keys 18 are retained in their normal uppermost position due to the magnetic attraction between the permanent magnet portion 24 and the ferromagnetic member 60. The operation of the apparatus illustrated in FIG. 3 is identical to that of the apparatus illustrated in FIG. 1.

Although the invention has been described with reference to specific embodiments, variations within the scope of the following claims will be apparent to those skilled in the art.

I claim:

1. Control apparatus comprising: a pair of elongated members in opposed, spaced-apart relationship; one of said members being fixed and the other of said members being movable; at least one actuator movable in a direction generally perpendicular to the relative direction of movement of said members from a first position adjacent one of said members to a second position adjacent the other of said members; said actuator including a permanent magnet portion with at least two spaced poles of opposite magnetic polarity; said other member having at least a pair of spaced magnetic poles of substantially equal pole pitch to those of said permanent magnet portion, the poles of said other member being opposed to the poles of said magnetic portion when said other member is in one position of its movement whereby to attract and hold said actuator when it is moved toward said other member and of like polarity when said other member is moved to a second position whereby said actuator is repelled away from said other member the distance between said first and second positions of said other member being approximately equal to at least one pole pitch.

2. The apparatus of claim 1 wherein said one of said members is of magnetically attractive material and said actuator is held on said first position by the magnetic attraction of said magnetic portion therefor.

3. The apparatus of claim 2 wherein said material is magnetizable and is magnetized to present magnetic poles of opposite magnetic poles to said magnetic portion.

4. The apparatus of claim 2 wherein said material is magnetically permeable.

5. The apparatus of claim 2 wherein said magnetic portion has two pairs of magnetic poles, each facing one of said members.

6. The apparatus of claim 2 wherein said one member carries said actuator.

7. The apparatus of claim 6 wherein said actuator is slidably supported by said one member.

8. The apparatus defined in claim 1, wherein said actuator is carried by said fixed member.

9. The apparatus defined in claim 1, wherein said movable member further includes biasing means for automatically returning said movable member from said second position to said first position.

10. The apparatus defined in claim 1, further including a magnetically actuated switching device having open and closed positions in operative magnetic association with said permanent magnet portion when said actuator is in one of its positions whereby when said actuator is moved from its first position to said second position said device is actuated.

11. The magnetic contact apparatus defined in claim 10, wherein said switching device comprises a reed switch.

12. The magnetic contact apparatus defined in claim 1, wherein at least one of said members and said permanent magnet portion are constructed from plastic-bound permanent magnet material of high coercive force.

13. Control apparatus comprising: a first elongated permanent magnet member having a plurality of spaced magnetic poles and a magnetically attractive second member substantially coextensive therewith; said second member being fixed and said magnet member being longitudinally movable and in opposed, spaced-apart relationship with respect thereto; at least one actuator carried by said second member for selectable magnetic retention by either of said members; said actuator including a permanent magnet portion with at least two poles of alternating polarity and being displaceable in a direction generally perpendicular to the direction of longitudinal movement of said magnet member; said poles on said magnet member and said magnet portion being of substantially equal pole pitch and so arranged that said magnet portion has poles which face said poles on said magnet member which are unlike when said magnet member is in a first position and which are like when said magnet member is in a second position, the distance between said first and second positions being approximately equal to at least one pole pitch.

14. The apparatus of claim 13 wherein said second member is of ferromagnetic material.

15. The apparatus of claim 13 wherein said second member is of magnetic material having spaced magnetic poles of equal pole spacing but opposite magnetic polarity to said poles of said magnet portion when said actuator 15 magnetically retained by said second member.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3 588 766 Dated June 28, 197].

Inventor(s) MAX BAERMANN It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Claims priority, application Germany, filed October 21, 1968,

Serial No. P 18 04 228.9

Signed and sealed this 16th day of April 1971 (SEAL) Atte st:

EDWARD M.FLETOHER,JR. C. MARSHALL DAMN Attesting Officer Commissioner of Patents

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