U.S. patent number 3,811,024 [Application Number 05/356,734] was granted by the patent office on 1974-05-14 for momentary contact, non-bounce switch.
This patent grant is currently assigned to Alco Electronic Products, Inc.. Invention is credited to Henry J. Sevigny.
United States Patent |
3,811,024 |
Sevigny |
May 14, 1974 |
MOMENTARY CONTACT, NON-BOUNCE SWITCH
Abstract
A novel switch, particularly useful for achieving reliable,
reproducible, momentary contact, as is desirable in the operation
of electronic keyboard actuators. The switch is characterized by a
spring means carrying a weighted contact which, on being biased by
a cam in a first direction away from a contact, is allowed to snap
back, with a predetermined and inherent momentum, beyond its normal
position to make a momentary electrical connection with a
stationary contact and thereby make a temporary circuit through the
switch.
Inventors: |
Sevigny; Henry J. (Salem,
NH) |
Assignee: |
Alco Electronic Products, Inc.
(North Andover, MA)
|
Family
ID: |
23402725 |
Appl.
No.: |
05/356,734 |
Filed: |
May 3, 1973 |
Current U.S.
Class: |
200/510;
200/521 |
Current CPC
Class: |
H01H
15/102 (20130101); H01H 13/506 (20130101) |
Current International
Class: |
H01H
15/00 (20060101); H01H 15/10 (20060101); H01H
13/50 (20060101); H01h 015/06 () |
Field of
Search: |
;200/77,78,160,153L,153LA,153B |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Schaefer; Robert K.
Assistant Examiner: Tolin; Gerald P.
Attorney, Agent or Firm: Pearson & Pearson
Claims
1. In a momentary contact switch comprising an insulating support
and at least one pair of electrical contacts mounted in said
support, adapted to be contacted momentarily, the improvement
wherein:
a first of said pair of contacts is attached to a deflectable
member;
a switch actuating member comprises means for deflecting said
deflectable member a predetermined distance from its normal
position, and means for releasing said deflectable member after
said deflection; and
a pendular mass associated with said member and forming means to
carry said deflectable member back through its normal position and
carry said first contact into said momentary contact with a second
of said pair of
2. A switch as defined in claim 1, wherein:
said pendular mass forms the contact surface of the first of said
pair of
3. A switch as defined in claim 1, wherein:
said deflectable member is a rod carrying said pendular mass
proximate one
4. A switch as defined in claim 1, wherein:
said deflecting means is a cam assembly mounted for relative
movement against said deflectable member;
said cam being so shaped that, as it is moved relative to the
deflectable member, said member encounters a first cam surface
forming means to deflect said member in a first direction away from
said stationary contact, and then encounters a sharp recess in said
cam forming means to release said member inwardly along a second
cam surface toward said stationary contact; and
wherein said second cam surface and a fixed cam member are mounted
for relative movement with one another to form means to urge said
deflectable
5. A switch as defined in claim 3, wherein:
said deflecting means is a cam assembly mounted for relative
movement against said deflectable member;
said cam being so shaped that, as it is moved relative to the
deflectable member, said member encounters a first cam surface
forming means to deflect said member in a first direction away from
said stationary contact, and then encounters a sharp recess in said
cam forming means to release said member inwardly along a second
cam surface toward said stationary contact; and
wherein said second cam surface and a fixed cam member are mounted
for relative movement with one another to form means to urge said
deflectable
6. Apparatus as defined in claim 1, wherein:
said switch is free of any contact-making means except that formed
by the
7. Apparatus as defined in claim 4, wherein:
said fixed cam is integral with said insulating support member;
and
said cam assembly is biased against a return spring, positioned
between
8. Apparatus as defined in claim 1, wherein:
9. Apparatus as defined in claim 1, wherein:
the deflectable contact member is fixed to said support proximate
one end
10. Apparatus as defined in claim 4, wherein:
said cam assembly is adapted to immobilize said deflectable member
when said switch is not in use;
said immobilization being achieved by said deflectable member being
in
11. Apparatus as defined in claim 5, wherein:
said switch is free of any contact-making means except that formed
by said
12. Apparatus as defined in claim 3, wherein:
said switch is free of any contact-making means except that formed
by the
13. A momentary contact, non-bounce switch comprising:
a pair of electric contacts each including a relatively heavy
weight carried at the free end of a stiff rod spring, the other
ends of each said rod being anchored against movement;
plunger cam means mounted in said switch for reciprocal movement,
said means having a pair of inclined cam faces each arranged to
flex one of said contacts sidewise and then release the same;
a pair of stationary contacts in said switch, each in the path of
one of said movable contacts and arranged to momentarily close a
circuit when one of said movable contacts is released by said cam
means to flex thereagainst; and
a pair of stationary cam faces in said switch, operatively
associated with said plunger cam means, to prevent said electric
contacts from striking said stationary contacts more than once.
Description
BACKGROUND OF THE INVENTION
A great deal of development work has been directed toward the
manufacture of improved impulse switches. By "impulse switch" is
meant a switch which on being actuated, as by finger pressure, will
deliver a single contact having a duration not dependent upon a
manual de-activation of the switch, for example not dependent on
the release of finger pressure from a switch activating button.
Such switches are much in demand for use in operating fast
electronic apparatus and particularly in demand for so-called
electronic keyboards wherein a large number of such switches are
assembled. One of the desirable characteristics of these is that
they deliver reproducible signals which are as little dependent as
is possible upon the touch of the operator. And, of course, since
so many of these switches are assembled onto a switchboard, it is
important to achieve such desirable operating characteristics at as
low a cost as possible.
Among switches known in the art, most have an "on time" which is
dependent in part upon the speed at which the operator depresses or
otherwise manipulates the switch-actuating button. For example, see
such switches as are described in U. S. Pat. Nos. 2,616,009,
3,142,743, and 3,375,340, to Roeser, Borges and Wright,
respectively. Switches which do not have this feature are usually
of relatively expensive or complex design or have some other
limiting feature. For example, see U. S. Pat. No. 3,073,935 to
Smusz which relies upon a permanent magnet to restrain motion and
position of the contact members.
SUMMARY OF THE INVENTION
Therefore, it is an object of the invention to provide an improved
impulse switch.
It is a further object of the invention to provide an inexpensive
impulse switch adapted to yield a constantly reproducible output
signal despite operating habits of the switch operator.
Another object of the invention is the provision of an improved
switch, the operation of which is free of spurious signals caused
by "bounce" of a contact element.
It is still another object of the invention to provide a switch
having the advantages described in the foregoing paragraphs and
which, on being actuated, responds to the touch in such a manner as
to confirm actuation by a tactile feeling to the switch
operator.
Other objects of the invention will be obvious to those skilled in
the art on reading this application.
The above objects have been substantially achieved by construction
of a switch wherein a pendular mass and a contact making member are
mounted for biased movement on a deflectable member. As the switch
is actuated, the pendular mass is initially biased, on its
deflectable carrying member, away from a stationary contact. As the
actuation stroke reaches a predetermined position, the pendular
mass is released; thereupon it carries the deflectable member back
beyond its normal pre-actuation position and causes it to strike
the stationary contact with an exactly reproducible stroke related
to the mass of the pendular member and resiliency of its carrier,
and then to spring away from the stationary contact.
ILLUSTRATIVE EMBODIMENT OF THE INVENTION
In this application and accompanying drawings, there is shown and
described a preferred embodiment of the invention and suggested
various alternatives and modifications thereof, but it is to be
understood that these are not intended to be exhaustive and that
other changes and modifications can be made within the scope of the
invention. These suggestions are selected and included for purposes
of illustration in order that others skilled in the art will more
fully understand the invention and the principles thereof and will
be able to modify it in a variety of forms, each as may be best
suited in the condition of a particular case.
IN THE DRAWINGS
FIG. 1 is a plan view of a non-bounce switch constructed according
to the invention;
FIG. 2 is a side elevation, in section, taken along lines 2--2 of
FIG. 1;
FIGS. 3, 4, and 5 are similar to FIG. 2, but show the sequence of
operation of the switch;
FIG. 6 is a side elevation, in section, on lines 6--6 of FIG.
1.
Referring to FIG. 1, it is seen that an impulse switch 10 comprises
a housing 12 which forms an electrically insulating support and
within which are positioned two fixed electrical contact elements
14 and 15 and two movable electrical contact elements 16 and 17.
Movable contacts 16 and 17 are each carried on deflectable
conductive rods 18 or 19. Each of rods 18 or 19 has one end 20 free
to move in housing 12; the other end 22 is attached to a fixed
electrical terminal 24 or 25 which is partially embedded within
housing 12.
As seen in FIG. 2, cam assembly 26 is preferably centrally mounted
in housing 12 and is connected to an operating rod 28 which, in the
usual practice, will be attached to a push-button, or key, 30. As
seen in FIG. 3, integrally molded into housing 12 are stationary
cam surfaces 32 and 33. Surfaces 32 and 33, as will be seen, form
means to guide rods 18 or 19 to their normal position when the cam
assembly 26 is pushed upwardly by return spring 34 which is mounted
between the operating rod 28 and the bottom of housing 12.
Cam assembly 26 comprises an operating head 36 which not only
carries primary cam surfaces 38 and 39 (as shown in FIG. 2 to be in
contact with rods 18 or 19), but also carries an upper surface 40
and 41 which acts with stationary cam surface 32 or 33 to position
rods 18 or 19 on the upper stroke thereof and a restraining surface
42 or 43 which is adapted to restrain rods 18 or 19 in snug
position after each switching sequence, as will be disclosed more
fully below.
In a typical operational sequence, switch 10 is first in the
position shown in FIGS. 1 and 2. Rods 18 and 19 rest against
restraining surfaces 42 and 43 of cam assembly 26, just about where
surfaces 42 and 43 and cam surface 38 and 39 join. In this
position, as best seen in FIG. 1, there is a substantial gap
between electrical contacts 14 and 16 and electrical contacts 15
and 17. The impulse switch, as a consequence, is in its normally
open mode. Then, as operating pressure is applied to push-button
30, operating rod 28 is depressed and rods 18 and 19 each slide
outwardly along a cam surface 38 or 39. During this depression of
the cam operating head 36, spring 34 is compressed, but the
resistance of spring 34 is small compared to the total force
required to depress operating head 36 against the resistance of
rods 18 and 19. As the depression of operating head 36 continues,
the free ends 20 of rods 18 and 19 are biased outwardly toward the
housing carrying with them movable contact-bearing members 16 and
17. When operating head 36 is depressed to the upper edge of
primary cam surfaces 38 and 39 (as seen in FIG. 3), outward biasing
pressure on rods 18 and 19 is maximized and then (as seen in FIG.
4) this pressure is suddenly removed as the operating head is
depressed still further to allow the inward movement of operating
rods 18 and 19, a movement roughly parallel to surface 40 and 41.
This movement is not arrested until contacts 16 and 17 have snapped
back to contact, and hence close a circuit with, stationary
contacts 14 and 15. This contact is temporary and rods 18 and 19
immediately bring the contacts 16 and 17 back to their normal
position, i.e. the position shown in FIG. 1.
At the time that rods 18 and 19 are no longer being biased apart by
pressure of the operator on push-button 30, a trained operator will
sense a sudden release of pressure and remove his finger from the
push-button. His release of the button, however, has no effect
whatsoever on the time of contact between contacts 16 and 17 and
contacts 14 and 15. That time was predetermined by the mass and
velocity imparted to contacts 16 and 17 by the energy stored in
rods 18 and 19, the elasticity of the contacts themselves, and
other such predetermined physical characteristics of the switch. It
should also be noted that the rate of speed at which the button was
depressed is of no consequence since the rods 18 and 19 are
selected so that they remain in contact with cam surfaces 38 and 39
throughout any foreseeable rate of actuating movement.
In any event, after contacts 16 and 17 hit contacts 14 and 15, they
return to their original position and, at about the same time,
spring 34 compressed by the actuating stroke of the pushbutton, is
released and commences the returning of cam assembly 26 to its
original position. As the cam 26 moves upwardly, rods 18 and 19 are
forced against stationary cam surfaces 32 and 33 by upper surface
40 of cam 36. Consequently, the rods 18 and 19 are again strained
outwardly (as shown in FIG. 5); this time, however, they are being
pushed outwardly along upper surfaces 40 by cams 32 and 33. When
rods 18 and 19 reach the edge formed by the juncture of surfaces 40
and 41 and 38 and 39, they slide downwardly to their starting
position at restraining surface 42 and 43. In this position rods 18
and 19, and hence contacts 16 and 17, are held snugly to prevent
movement or damage.
It is to be understood that the following claims are intended to
cover all of the generic and specific features of the invention
herein described and all statements of the scope of the invention
which might be said to fall therebetween.
* * * * *