05/005431

11/02/1971

01/23/1970

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International Business Machines Corporation (Armonk, NY)

200/1R

200/46, 200/86R, 200/512, 341/34, 200/5R

H01H13/702; H01H13/70; H01H43/08; H01H9/00; H01H3/12

200/1,5,46,52,83.8,86,86.1,159B,159A,159,18,61,43,172 179/9K 178/17 235/145

3350518	Reader for punched record	October 1967	Krakinowski et al.
3382338	Pushbutton actuator for elastomeric switch	May 1968	Arseneault et al.
3494550	UNIVERSAL KEYBOARD	February 1970	Hayes et al.
3472974	PUSHBUTTON SWITCH ACTIVATED BY A SLIDE WITH A PLURALITY OF TOGGLE JOINTS AND CAMS	October 1969	McGough

Scott J. R.

What is claimed is

1. An apparatus for actuating a diaphragm switch device comprising:

2. An apparatus for actuating a diaphragm switch comprising:

3. Means for actuating an array of diaphragm switch contacts comprising:

4. Means for actuating an array of diaphragm switch contacts comprising:

5. Manual data input apparatus comprising:

6. Manual data input apparatus comprising:

7. A keyboard, for data entry including as follows:

8. A keyboard for data entry including as follows:

9. Apparatus in accordance with claim 8 wherein said means for stopping comprises a plurality of additional projections.

10. Apparatus in accordance with claim 9 wherein said additional projections are shorter than said first named projections.

11. Apparatus in accordance with claim 10 wherein a rigid frame with key holes is disposed between said keyboard means and said actuator member to provide separation.

12. Apparatus in accordance with claim 11 wherein a plurality of soft elastomeric pads couple said keyboard means and said actuator member through said key holes.

13. A device operable selectively for closing pairs of contacts of an array of contacts comprising, in combination:

14. The device of claim 13 having a rigid frame member in said trough areas.

15. The device of claim 14 having an elastomer indicia bearing member overlaying said deformable operator member and said rigid frame and having an indicia area in alignment with each said operating area of said deformable operator.

16. A device operable selectively for closing pairs of contacts of an array of contacts comprising, in combination:

17. The device of claim 16 having a rigid frame member in said trough areas.

18. The device of claim 17 having an elastomer indicia bearing member overlying said deformable operator member and said rigid frame and having an indicia area in alignment with each said operating area of said deformable operator.

19. A device operable selectively for closing pairs of contacts of an array of contacts comprising, in combination:

20. The device of claim 19 having a rigid frame member in said trough areas.

21. The device of claim 20 having an elastomer indicia bearing member overlaying said deformable operator member and said rigid frame and having an indicia area in alignment with each said operating area of said deformable operator.

BACKGROUND OF THE INVENTION

1. Field of Invention

This invention relates to keyboards for providing input of data to electrical apparatus and more particularly to such keyboards employing diaphragm switches and the like.

2. Description of Prior Art

Diaphragm switches of the kind described in commonly assigned Krakinowski U.S. Pat. No. 3,308,253 have heretofore been included in keyboard designs as shown in Arsenault et al. U.S. Pat. No. 3,382,338, Hayes et al. United States patent application Ser. No. 609,216 filed Jan. 13, 1967 now U.S. Pat. No. 3,451,168 and Yarborough U. S. Pat. application Ser. No. 767,755 filed Oct. 15, 1968 now U.S. Pat. No. 3,517,149 which provide each key position with a separate keying mechanism, including a keying surface, an elastic coupling medium, and an actuator. Special devices must be incroporated to protect the switch from overload by the user.

An object of this invention is to provide an integrated keying mechanism serving all keys in an array with common parts to reduce the number of parts, simplify the structure and simulate to the user the response of the mechanism to his operation thereof in terms of manual force and pressure required for operation, pretravel, overtravel, variable touch, and the effect of a key stop to that provided by conventional keyboard operated apparatus such as typewriters.

Another object of this invention is to provide a simplified electrical keyboard incorporating means for protecting the contact mechanism from excessive force applied to the keying surface.

A further object of this invention is to provide an integrated keying mechanism including means for prevention of interaction between the keying mechanism for one set of contacts and adjacent unrelated contacts.

Still another object of this invention is to enhance the uniformity of manual pressure required to achieve contact closure so that in the event of offcenter operator keying strokes on the keying surface of the keyboard closure will occur for a force equal to that required when the stroke is on center.

Another object of this invention is a keyboard capable of absorbing high impact blows upon the keying area without damage to the mechanism.

Further a keying mechanism with a bounceless actuator is desired, in order to minimize transmission of vibratory forces to the contacts.

SUMMARY OF THE INVENTION

In accordance with this invention, a keyboard apparatus is provided including means for keying in data, an actuator for actuating an array of switches, a plurality of diaphragm switches, and deformable means for coupling the actuator member and the switches.

Further in accordance with this invention, a plurality of elastomeric projections from the actuator cooperate with the switches and means are included within the actuator member for stopping the actuator member after a predetermined degree of travel has occurred to minimize coupling of the stress pattern to adjacent projections.

Still another aspect of this invention relates to a separator frame and a plurality of keying pads provided for alignment with the protrusions upon the actuator for desirable manual keying action.

In another aspect of this invention, peripheral means about one or more protrusions provide means for supporting the actuator after a predetermined degree of displacement, and for spreading force applied over a substantially greater area.

The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention, as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a vertical section of an integrated keyboard formed of an array of diaphragm switches with a single actuator member incorporating an array of protrusions thereon with a plurality of keys above the actuator.

FIG. 2 shows a top plan view of the keyboard shown in FIG. 1.

FIG. 3 shows a graph of force applied to a key as shown in FIGS. 1 and 2 as a function of displacement of the upper surface of the actuator sheet beneath that key.

FIG. 4 shows force required on a particular key as a function of lateral displacement from the center of the key along a key diameter.

FIG. 5A shows a vertical section of the actuator and diaphragm switch shown in FIGS. 1 and 2.

FIG. 5B is a bottom plan view taken along lines 5B--5B in FIG. 5A showing the bottom of the actuator.

FIG. 6A is a vertical section of a modified actuator and switch including a plurality of contact positions per key.

FIG. 6B is a bottom view of the actuator of FIG. 6A taken along line 6B--6B.

FIG. 7A is a vertical section of a further modified actuator and switch for a square key with plural contacts taken along line 7A--7A in FIG. 7B.

FIG. 7B is a bottom plan view taken along line 7B--7B in FIG. 7A.

FIG. 7C is a vertical section of the embodiment of FIG. 7A at right angles to FIG. 7A taken along line 7C--7C in FIG. 7A.

FIG. 8 shows a vertical section of a further modified actuator and switch.

FIG. 9A shows a vertical section of a modified actuator and switch with a ring-shaped rib concentric with the central actuating protrusion in place of the peripheral protrusions.

FIG. 9B shows a bottom plan view taken along line 9B--9B in FIG. 9A.

FIG. 10A shows a vertical section of a modified actuator and switch with a hollow about the central actuating protrusion and an elevated surface between hollows.

FIG. 10B shows a bottom plan view taken along line 10B--10B in FIG. 10A.

FIG. 11 is a vertical section of a rigid actuating protrusion projected to actuate a diaphragm switch.

FIG. 12 is a vertical section of a sharp edged rigid actuator projected to actuate a diaphragm switch.

FIG. 13 is a vertical section of another smaller cross section sharp edged actuator projected to actuate a diaphragm switch.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

In FIGS. 1 and 2 a keyboard 10 with soft flexible keys 11 permits operation of soft buttons 16 to press down protrusions 21 of actuator 20 to operate diaphragm switches 28 comprising diaphragm 23 with contacts 24, separator sheet 25, and contacts 27 on sheet 30 on base 29.

The keyboard is shown in vertical section in FIG. 1 and in a fragmentary plan view in FIG. 2 with a polyurethane elastomer nomenclature sheet 10 preferably about 0.010 inch to 0.03 inch thick with indicia bearing keys 11 about 5/8 inch in diameter to be manually operated. The nomenclature sheet 10 defines visual keying areas 11. The polyurethane elastomer is preferred because it is tough, wears well and allows for large localized deformation without affecting adjacent keying positions. The nomenclature sheet 10 is part of the keying mechanism designed to be freely removable, at will, for replacement by another such unit bearing different indicia so that the keyboard can be used for a multiplicity of purposes. In addition, unlike overlays, the indicia and the keys are replaceable, allowing the indicia to be printed directly on the key where keying mechanisms are interchanged.

Below the sheet 10 is a protective sheet 14 (0.005-0.010 inch thick of elastomer) serving as a dust cover sealing the actuating mechanism below from the environment and facilitating manipulation of the sheet 10.

Under protective sheet 14 is a rigid frame member 15, preferably of aluminum, having circular (or square) holes 17 therein aligned concentrically with keys 11 to permit keys 11 to be depressed therethrough, which in combination with keys 11 and buttons 16 defines tactile keying areas corresponding to the visual keying areas 11.

Extending through circular holes 17 are key buttons 16 formed of a very soft elastomer molded integrally in a pad 18. The elastomer is preferably composed of a closed-pore cellular neoprene rubber (one-eighth inch-one-quarter inch thick) with a low compressive modulus on the order of ASTM SC-011-SC-013.

Below the pad 18 is an actuator sheet 20 comprised of a molded preferably neoprene rubber or elastomer having a medium hardness of about 55-65 durometer about one-sixteenth inch thick having a plurality of clusters of truncated cone-shaped protrusions 21, 22 with one protrusion 21 in the center and four preferably slightly shorter protrusions 22 spaced thereabout as shown in FIGS. 5A and 5B. Each protrusion 21 is aligned with the centers of keys 11, holes 17 and key buttons 16. The outer protrusions 22 are in a circle about 3/8 inch diameter spaced about the central protrusion 21. Preferably the central protrusion 21 is about 6 to 10 mils longer than one-eighth inch and the other protrusions are 1/8 -inch long. Protrusions 21 when depressed move contacts 24 into contact with contacts 27 of switches 28 which are elastic diaphragm switches described next, herein.

Below the actuator 20 is an array of diaphragm switches including diaphragm 23 of elastic material, preferably Mylar polyester, which is 0.002 to 0.003 inch thick, and is copper clad (with gold plating) 0.0014 inch thick to form contacts 24 and connections thereto, the the contacts 24 below protrusions 21. Below diaphragm 23 is a Mylar separator sheet 25 preferably 0.003 inch thick having a plurality of holes 26 therein 5/32 inch in diameter aligned coaxially with protrusions 21. Diaphragm 23 is spaced from spacer 25 and sheet 30 is spaced therefrom by the copper members 24 and 27 which extend beyond the holes 26 on either side thereof as shown in FIG. 7C and which are sufficiently stiff to hold the diaphragm above holes 26 when control protrusions 21 are not depressed. Below separator sheet 25 is sheet 30 on a base 29 of molded plastic bearing contacts 27 which are copper clad with gold plate 0.0014 inch thick.

The combination of the very soft key pads 16 and the actuator sheet 20 of medium hardness rubber provide a relatively long keying stoke with pretravel and overtravel, as shown in FIG. 3. The soft buttons 16 and the flexible keys 11 provide a combination of actuating elements with a low spring constant, and long stroke, which depends upon the stiffness of buttons 16 and keys 11. An efficient method of adjusting the force-deflection characteristics or the "feel" of the keying mechanism to requirements is to vary the gap between the sheet 14 and buttons 16 so a selected key 11 must deflect before any force is transmitted down to the associated switch. Another method is to vary the ratio of stiffnesses between actuator 20 and pad 18, by geometry or by changing the stiffness of the material.

The actuator sheet 20 with the discrete projections 21, 22 concentrates the actuating force on the switches 28. This arrangement permits relatively large keying areas for each key position. The keying area can be 5/8 -inch diameter for a switch area of only one-eighth inch to one-fourth inch. The actuating force required to operate a switch is essentially constant over the surface of a keying area as illustrated by FIG. 4, based upon a specific switch which was tested which does not necessarily show the general variation but simply is illustrative. However, because of projections 22, the actuating force remains constant over the surface of each of the keys 11. As indicated in FIG. 5A, and FIG. 5B, the cluster of protrusions 21, 22 is well within the projected cylinder defined by the keys 11. The peripheral protrusions 22 are slightly shorter than the central protrusion 21 which actuates its switch. These protrusions 22 serve as key stops so that the actuator sheet 20 and projection 21 can be stopped from excessive depression below the level necessary to close contacts 24 and 26, so that force can be spread out to protect the switches 28, and so that the adjacent protrusions 21 will be prevented from closing their switches by general lowering of actuator 20 in the areas surrounding the associated button 16. The protrusions 22 will tend to act as a fulcrum causing areas outside the "ring" of a cluster to rise rather than fall. Since protrusions 22 are shorter, they facilitate closure by the central protrusion 21.

As force is applied, it is distributed as desired, and until protrusions 22 contact the switch 20, force is concentrated on actuators 21. However, as forces are increased, the forces are spread out onto stops 22 so that the greater forces are distributed over a relatively larger area of sheet 23 and switch 28 by stops 22.

FIG. 3 shows the action of the keying mechanism as the force applied on the vertical axis versus the displacement of the top surface of actuator 20 with pretravel, (prior to closure, and overtravel after closure). At the end of the flat portion of the curve (after the switching point) the rise reflects the load redistribution that occurs.

When the actuator protrusion 21 is depressed upon diaphragm 23, the protrusion 21 must be sufficiently deformable and visco-elastic so that it will produce minimal extrusion of the copper and the diaphragm 23 and will permit very long diaphragm life. The hole 26 is large enough in diameter so that an overall clearance between the protrusion 21 and the edge of the hole 26 keeps the deflection stress on the copper and the deflected diaphragm below a critical value.

FIGS. 6A and 6B show a vertical section and a bottom plan view of a modified actuator sheet 20 with a larger cluster of protrusions with five central protrusions 21 and eight peripheral protrusions 22 for operating five sets of contacts in diaphragm switch unit 28. This arrangement is desirable for larger keying areas, or where it is desired to assure even a more uniform degree of equality of actuating force required to close at least one set of contacts to be applied over the area of a key 11.

FIG. 7A shows a vertical section along lines 7A--7A in FIG. 7B and FIG. 7B shows a bottom plan view of a modified arrangement of the actuator sheet 20 which is suitable for use in a similar keyboard with square keys. Instead of peripheral protrusions, however, a stop is formed by a rib 32 inside the area of a key 33 shown in phantom, with the central protrusions 21 arranged as shown to fill the area inside rib 32. The rib 32 serves as a stop which prevents actuation of or by adjacent key areas and which absorbs overtravel forces as described above.

FIG. 7C shows a vertical section along line 7C--7C in FIG. 7A which shows how contacts 24 and 27 bear against separator 25 to maintain separation of the diaphragm 23, separator 25 and sheet 30.

FIG. 8 shows a further modified version of the actuator sheet 20 with the stops 34 formed integrally with the central protrusions 21, so that overtravel will not pull down adjacent protrusions 21, because stops 34 will prevent further depression of the actuator 21 then operating the contact which is then switching from deflecting sheet 20 materially, and whereby stops 34 absorb and spread overtravel forces to protect the switch.

FIG. 9A shows a vertical section and FIG. 9B shows a bottom plan view of an actuator sheet 20 having central protrusions 21 surrounded by individual peripheral protrusions 35 analogous to a large number of protrusions 22 merging together at a predetermined radius.

In FIGS. 10A and B, the radial rib 35 of FIG. 9 is replaced by a solid stop 36 between depressed areas 37 surrounding the central protrusions 21, whereby the protrusions are located in craterlike recesses in the lower surface of the actuator member 20.

FIG. 11 shows a hypothetical rigid member 40 which is not elastomeric, which is employed to depress the diaphragm 23, and it is shown at 41 that the copper 24 and the diaphragm 23 have been deformed. In a relatively short time, the copper will be permanently extruded or bent by such an actuator.

FIG. 12 shows a hypothetical rigid square actuator 42 with square corners 43 which would tend to tear the diaphragm 23 at corners 43, although it is wide enough to not deform electrode 23.

In FIG. 13, a third hypothetical rigid actuator 45 is shown with a flat lower surface 46 and edges 47 designed so that if it were perfectly aligned with the diaphragm 23 and the contact 24 that it would provide an even enough force on contact 24 to avoid deformation of the contact 24. However, in fact, in a mechanism with dozens of actuators, the probability of maintaining all actuators 45 in perfect alignment is exceedingly low; and furthermore, it is even lower that perfect alignment would persist. Thus, in short order, at least some of the switch contacts 24 would as in FIG. 13 be bent by a corner 47 at an angle which is exaggerated in FIG. 13, for convenience of illustration, to show the bending of contact 24 to provide a poor set of contacts.