Keyboard Reed Switch

Abstract

A pushbutton keyboard switch embodying an enclosed reed contact element mounted on a base portion of a switch in close proximity to a permanent magnet that is movably supported between a pair of opposing spring members, a slidable actuator being in contact with one of the spring members so as to compress the same against the magnet to increase its kinetic force until it overcomes the resistance of the opposing spring to effect longitudinal switching movement of the magnet relative to the reed contact element and to create a tactile feel in the movement of the actuator.

Description

SUMMARY OF THE INVENTION

A pushbutton keyboard switch used as a code generator for computing machines, electric typewriters, and the like, including a hollow housing open at one end, an elongated actuator movable through the housing in the direction of an insert base, with the latter adapted to carry one or more reed switch elements and their external terminals; the base also providing a retaining sleeve for a permanent magnet that is positioned between a pair of opposing coil springs which yieldably maintain the magnet in a first position relative to the reed contact elements. Within the housing is fixedly mounted a ferrous member that yieldably restricts movement of the magnet until a sufficient compression force is placed upon one of the opposing spring members by the moving actuator until such force overcomes the magnetic attraction between the magnet and the ferrous member as well as the resistance of the opposing spring, so as to result in an initial movement of the magnet and a tactile feel upon the actuator as a result of such movement.

GENERAL DESCRIPTION

The invention is disclosed in the accompanying drawing which shows the preferred form thereof, and in which:

FIG. 1 is a perspective view of the assembled keyboard pushbutton reed switch;

FIG. 2 is a perspective view of the components of the switch in an exploded relationship;

FIG. 3 is a side sectional detailed view of the assembled switch of FIG. 1;

FIG. 4 is a fragmentary side sectional view of a modified form of a keyboard pushbutton switch;

FIG. 5 is a detailed sectional view of the case taken on line 5--5 of FIG. 2;

FIG. 6 is a detailed sectional view of the case taken on line 6--6 of FIG. 2;

FIG. 7 is a top plan view of the base member of the switch as seen in FIG. 2 on line 7--7.

An assembled pushbutton keyboard reed switch is indicated at 10 in FIG. 1 and includes an actuator button 11 carried by the free end of an actuator lever 12.

As seen in FIGS. 2 and 3, the actuator button 11 provides an internal bore 13 into which is press-fitted the formed end 14 of the actuator lever 12. The switch 10 is housed in a two-piece hollow casing 15. The top wall 16 provided by the casing 15 has formed therein a slot 17 through which the actuator lever 12 slidably projects.

Referring to FIG. 6, it is seen that each piece of the casing 15 provides an internal partition 18 and 19 which, when mated, provide therebetween a slot 20 that communicates with the slot 17 formed in the top wall 16 of the casing 15, as well as a circular center bore 21. The circular bore 21 terminates at its inner end into a countersunk recess 22 (see FIG. 5). Each partition 18 and 19 includes depending wall members 23 that extend along the major portion of the side walls of the casing pieces. These depending wall members 23 of each of the partitions 18 and 19 form therebetween channels 24 which receive the foot portions 25 carried at the ends of the leg sections 26 of the actuator lever 12. As shown in FIGS. 2 and 3, the leg sections 26 of the actuator lever 12 are spaced apart a distance sufficient to extend through the slot 20 formed between the partitions 18 and 19 but not through the slot 17 formed in the top wall 16 of the casing 15.

Between the leg sections 26 of the actuator lever 12 and extending in parallel relation with respect thereto, is a stud 27. This stud 27 is positioned within the circular bore 21 formed by the partitions 28 and 19 of the casing 15.

Adapted to close the open end of the housing for the switch 10 is an insertable base 28. This base, like the housing, is preferably made of molded plastic material and is therefore nonconductive and nonmagnetic. The base 28 provides as an integral molded part thereof an upstanding split sleeve 29. On opposite edges of the split sleeve 29, the wall portions thereof are formed to provide a semicircular recess 30 which extends throughout the length of the sleeve 29. Spaced from these recesses 30 and extending in a parallel relation to the sleeve 29, are a pair of corner posts 31 and 32. The corner posts each provide a confronting semicircular wall surface 33 which cooperates with the semicircular recesses 30 provided by the sleeve 29 to form an elongated receptacle for a glass-enclosed reed switch element 34. One end of the reed element 34 is connected to an external pronglike terminal 35 which extends through the base 28. The other end of the reed switch element 34 is connected to a end 36 of a conductive terminal 37 which extends along a portion of the sleeve 29 and which terminates into similar pronglike terminals 38 externally of the base 28.

Within the sleeve 29 is inserted a coil spring 39 which supports a circular bar-type permanent magnet 40. This magnet 40 is supported by the spring 39 in a position relative to the contact members of the reed switch such that they are normally spaced from each other so as to represent an open switch. However, the reverse may be true without departing from the invention. The construction of the reed switch element is well known in the art and makes up no part of the present invention except for its functional relationship to the overall structure herein described.

Within the countersunk recess 22 provided by the partitions 18 and 19 is press-fitted a metal ring 41 to which is magnetically attracted the magnet 40. Journaled within the center of the ring 41 and coiled about the stud 27 provided by the actuator lever 12 is a second coil spring 42. When the parts are thus assembled, they will be in the condition shown in FIG. 3 of the drawings.

When the base 28 is inserted on and closes the bottom of the housing, the terminal ends 36 will be positioned in compartments 43 formed in the upper end of the casing 15 by partitions 18 and 19. The partial slit 44 forming the split sleeve 29 will align itself with the channels 24 formed between the wall members 23.

Application of an external force upon the actuator button 11 will cause slidable movement of the actuator lever 12 into the housing. The foot portions 25 of the actuator lever 12 will be guided through the channels 24 and the slit 44 when the actuator button 11 is depressed with the actuator lever 12 moves through the switch casing 15.

The spring 42 will be compressed between its contact with the actuator lever 12 and against the magnet 40 seated upon the spring 39, and, with continuing movement of the actuator lever 12, the end of the stud 27 carried thereby will contact the top of the magnet and move it off the ring 41. By compressing the spring 42, the kinetic force thereof is increased until it is sufficient to overcome the now gapped magnetic attraction between the magnet 40 and the metallic ring 41.

The bottom of the slit 44 will act as a stop for travel of the actuator lever 12, at which point the magnet 40 will have become displaced with respect to the reed switch 34 so as to effect actuation thereof.

When the magnet 40 is forcibly released from its connection to the ring 41, a tactile feel of such releasing action will be transmitted through the actuator lever 12 onto the actuator button 11, indicating that the switch has been actuated to a point where the magnet 40 has been initially moved and that it will continue to be moved under the force of the spring 42 as well as the continuing movement of the actuator lever 12 so as to magnetically affect the switch contacts of the reed switch element 34.

Because of variance in spring force as well as magnetic fields, the magnet 40 may be moved from contact with the ring 41 solely by the increased kinetic force of the spring 42, without first having an airgap created between the magnet 40 and the ring 41 by the stud 27. In either instance, however, the switch will be actuated with a resulting tactile feel in the actuator.

In the event that one does not desire the tactile field resulting from the actuation of the switch, a keyboard pushbutton switch can be constructed from all of the basic components hereinbefore described, with the exception that, as shown in FIG. 4, a modified actuator lever 45 omits the stud 27 and provides a medial portion 46 that has one edge engageable in direct contact with the magnet 40. The movement and operation of the remaining components of the switch remain the same.

While we have illustrated and described the preferred form of construction for carrying our invention into effect, this is capable of variation and modification without departing from the spirit of the invention. We, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail ourselves of such variations and modifications as come within the scope of the appended claims.

Claims

Having thus described our invention, what we claim as new and desire to protect by Letters Patent is:

1. A keyboard pushbutton switch assembly comprising a housing for a sealed reed switch including switch elements movably responsive to a magnetic field, wherein the improvement comprises

a. an actuator depressible into the switch housing,

b. a magnet within the housing spaced from the reed switch so as not to magnetically attract the switch elements thereof,

c. a compressible member yieldably supporting said magnet within the housing relative to the reed switch,

d. a spring between said actuator and said magnet and compressible thereagainst to move the same within the housing against the force of said compressible member and into a position to magnetically actuate the switch elements of the reed switch,

e. and a metallic ring fixedly carried within the housing and having an attractive magnetic force between it and said magnet which yieldably resists the moving force of said spring as it is pressed against said magnet by movement of said actuator into the housing until such moving force assists said actuator in overcoming the magnetic attraction so as to move said magnet against said compressible member and into switch actuation position, said ring so positioned within the housing so that said spring projects therethrough and against said magnet.

2. A keyboard pushbutton switch as defined by claim 1, wherein the housing includes a split sleeve insertable into the housing and in which said compressible member and said magnet are carried and about which is mounted in parallel relation the sealed reed switch, and means cooperating with said split sleeve for frictionally holding the sealed reed switch in a predetermined relation with respect to the path of movement of said magnet.

3. A keyboard pushbutton switch as defined by claim 2 wherein there is included means provided by the housing for guiding said actuator in the path of movement axially of said compressible member.

4. A keyboard pushbutton switch as defined by claim 1, wherein said ring is adapted to be press-fitted into a seat provided within the housing in axial alignment with said magnet and said spring.

5. A keyboard pushbutton switch as defined by claim 4, wherein said ring is adapted to be press-fitted into a seat provided within the housing in axial alignment with said magnet and said spring.

6. A keyboard pushbutton switch assembly comprising a sealed reed switch including switch elements movably responsive to a magnetic field, a magnet within said switch assembly and a compressible member yieldably supporting the magnet in a position relative to the reed switch, wherein the improvement comprises

a. a sealed housing for the reed switch and the magnet and its compressible supporting member,

b. said housing providing an internal split sleeve which freely embraces the magnet and its compressible supporting member,

c. an actuator for the switch assembly having a bifurcated end, portions of which are adapted to reciprocally move between the confronting walls of said internal split sleeve,

d. means on said actuator between its bifurcated end portions for moving the magnet through said split sleeve against its compressible supporting member and into switch actuating position, and

e. means provided by said housing and cooperating with said split sleeve for frictionally holding the reed switch in spaced parallel relation to the magnet and its compressible supporting member and out of the path of reciprocal movement of said actuator.

7. A keyboard pushbutton switch assembly as defined by claim 6 wherein said means that cooperate with said sleeve for frictionally holding the reed switch in a predetermined position comprise an angled corner post spaced from said split sleeve and cooperating therewith to frictionally hold said reed switch in a predetermined position.

8. A keyboard pushbutton switch assembly as defined by claim 6 wherein said sealed housing provides means for guiding said actuator as it is reciprocally moved between the confronting walls of said split sleeve.