Patent Grant
6891117
This invention generally relates to a rocker-type switch, and more particularly, to one that utilizes a modular block subassembly that allows a product line to use interchangeable switch contact elements for configuring single pole, double pole, 3-way, and 4-way switches with minimal changes to surrounding parts and elimination of tolerance stack up in the switch mechanism.
The rocker-type electrical wall switch has long been known for its advantages of operating switch contacts through limited angular movement of a pivoted rocker, thus allowing the ends of the rocker to remain substantially flush in the rocker frame for aesthetics. U.S. Pat. No. 3,770,920 to Polliak disclosed a rocker-type switch in which the rocker is pivotally supported in a housing at a first pivot point, a movable plate supporting a contact brush is pivotally supported at a second pivot point in the housing, and a spring is compressed between a downwardly extending boss on the rocker and a lower end of the plate supporting the contact brush, so that the spring is movable under compression to bias the contact brush plate to opposite inclined positions in response to pivotal movement of the rocker between its up and down positions. The contact brush makes contact in each rocker position with a switch contact supported on a respective one of a pair of terminal plates to which respective wire leads are attached, in order to form a single-pole rocker-type switch.
U.S. Pat. No. 5,382,768 to Kurek et al. disclosed another rocker-type switch in which a rocker actuator arm is moved in response to movement of a rocker cover to move a slider back and forth to open and close one or more pairs of switch contacts. Rocker movement is controlled by a rocker cam leaf spring which has a cammed profile traversed by the rocker cam to move the slider between switch contact positions, lock the rocker and provide other desired functions. The rocker cam spring is housed in a spring chamber longer than itself, allowing the rocker cam spring to float. A fixed terminal assembly is engaged with a switch contact assembly against which the slider moves to make contact and thereby close the switch, or moves away from to open the switch. The terminal assembly can be implemented in single-pole, double-pole, and double-throw for 3-wire or 4-wire circuit arrangements. A sheet metal mounting strap provides a cradle-like support for holding the switch in a wall box.
U.S. Pat. No. 5,950,812 to Tanacan et al. disclosed another rocker-type switch in which a star-shaped spring provides the necessary forces to hold the rocker to a switch spacer and to couple the rocker to a movable contact arm. The movable contact arm is inserted in the switch spacer and makes contact between opposing switch contacts. The star-shaped spring is made of flat spring stock and is selectively bent with star-shaped bends to enable the various switch contact functions. A V-notch receives the end of the movable contact arm and moves the arm between the two switch contact positions as the rocker is operated.
While there have been many variations of and improvements to the rocker-type switch, the conventional rocker-type switch still has certain problems that remain to be solved. One main problem is that changing the arrangement of the rocker-type switch to single-pole, double-pole, 3-way, or 4-way switch configurations requires that different terminal plates or wiring arrangements be used with different insulative parts in the terminal housing subassembly, thereby requiring substantial change to or reconfiguration of the switch parts. Also, the manufacture of different insulative parts of expensive, high temperature plastic material increases the costs for the overall product line. The required assembly of different manufactured parts in different configurations also results in tolerance error stack-up when the parts are assembled together, thereby leading to problems in terms of fit and alignment of the parts and the switch contacts.
It is therefore a principal object of the present invention to provide a rocker-type switch that can be readily configured to single-pole, double-pole, 3-way, or 4-way switch arrangements with minimal change to the surrounding parts. Specifically, it is desired to provide a rocker-type switch in which a modular block subassembly is used with interchangeable switch contacts to enable reconfiguration for other switch configurations with only minimal change to the surrounding parts. It is another object of the invention to limit the manufacture of insulative parts of expensive, high temperature plastic material to a modular block subassembly that can be used for different switch configurations, thereby minimizing the costs for the overall product line. It is yet another object of the invention to eliminate tolerance error stack-up when parts are assembled together, thereby providing more accurate fit and alignment of parts and switch contacts.
In accordance with the present invention, an improved rocker-type switch comprises:
In a preferred embodiment, the improved rocker-type switch is configured with space to accommodate a pair of movable contact arms arranged side-by-side to be pivoted by a pair of respective actuator members held in the pivot member positioned widthwise on the underside of the toggle member. The modular block subassembly is configured with space to define two pairs of opposing switch contact positions arranged in parallel alongside each other.
The subassembly can be configured selectively with one or more block member(s) and switch contact plate(s) for single-pole, double-pole, 3-way, and 4-way switch configurations. The switch contact plate(s) are connected to the respective terminal plate(s) by clip and tab portions, or any other suitable means of establishing an electrical connection therebetween. For a single-pole switch configuration, one switch contact plate has one switch contact thereon that may be positioned at one switch contact position for one movable contact arm. For a double-pole switch configuration, two switch contact plates each have one switch contact thereon that may be positioned at one respective switch contact position for each of two movable contact arms. For a 3-way switch configuration, two switch contact plates each have one switch contact thereon that may be positioned at opposite switch contact positions for one movable contact arm. For a 4-way switch configuration, two switch contact plates each have two switch contacts thereon that may be positioned at respective opposing switch contact position for two movable contact arms.
In a preferred assembly of a 4-way switch configuration, the preferred modular block subassembly is assembled in “drop-in” fashion with an insulative top block member having upright walls defining hollow spaces for receiving the depending ends of the two movable contact arms therein, a top switch contact plate having switch contacts mounted on upright tabs which are inserted through respective slots in the top block member, an insulative bottom block member sandwiching the top switch contact plate between it and the top block member, and a bottom switch contact plate having switch contacts mounted on upright tabs which are inserted through respective aligned slots in the bottom and top block members to switch contact positions opposite those of the top switch contact plate. The bottom block member is joined to the top block member by any suitable means. Two terminal plates with wire clamp members are arranged on opposite lateral sides toward one end of the bottom housing part and connected to the respective switch contact plates. Two cradle half plates for the movable contact arms with wire clamp members are arranged on opposite lateral sides toward the other end of the bottom housing part and electrically coupled to the respective movable contact arms. The top and bottom housing parts are held together by a rigid outer strap and by a pair of drive pins that are inserted through holes in the strap and in the bottom housing part and fastened to corresponding fastener members in the top housing part.
The top and bottom block members of the modular block subassembly may be molded from high temperature plastic material. The top block member does not need to be changed for different switch configurations. Thus, the improved switch of the present invention can limit the costs of molding expensive insulative parts for a complete product line. Also, since the modular block assembly uses the same top housing parts, movable contact arms, terminal plates, contact arm plates, and rocker assembly for the different switch configurations, fabrication costs for the whole product line are reduced, and the problem of tolerance error stack-up is eliminated for the parts assembly. The design of the modular block subassembly and its encapsulation between the top and bottom housing parts also provide for substantial noise reduction in electrical hum, improved dielectric spacing between open electrical contacts, and elimination of distortion due to any over-torqueing when attaching electrical leads to the wire clamp members.
Other objects, features, and advantages of the present invention will be explained in the following detailed description of the invention having reference to the appended drawings.
Certain preferred embodiments of the improved rocker-type switch of the present invention are described in detail below. It is understood that many other variations and modifications could be implemented by those skilled in the field to which this invention pertains, given the principles of the invention disclosed herein.
Referring to
The bottom housing part 40 has outer walls made of electrically insulative material which define a central aperture (indicated generally by reference numeral 41) for holding a modular block subassembly therein (shown later) and side apertures for holding terminal plates for the switch. A pair of wire clamp members (posts and screws) 42 for switch contact terminal plates are provided on opposite lateral sides of the bottom housing part toward one end thereof (lower end in the drawing), and another pair of wire clamp members 44 for contact arm terminal plates are provided on opposite lateral sides toward the opposite end of the bottom housing part (upper end in the drawing) for attaching other terminal wire leads thereto. The outer strap 60 fits around the bottom and side walls of the bottom housing part 40 with end plates 61 projecting from opposing sides of the joined housing parts for mounting to a wall box.
Forming the toggle subassembly, the toggle member has a central pivot member 24 extending across its lateral width and provided with two downwardly-facing recesses (not visible in the drawing) for holding a pair of actuator members 25 and biasing springs 26 therein that are used to pivot the movable contact arms 29a, 29b between opposing switch contact positions in response to up and down movement of the toggle member 21. The top housing part 20 has frame 22 with walls defining a rectangular cavity in which the toggle member is seated. The ends of the central pivot member are movably seated in and constrained for rocking movement within the triangular volume defined by the triangular posts 24a formed adjacent each side wall of the frame 22. On the floor of the rectangular cavity is a stiffening rib 27 extending lengthwise in the top housing part for structural rigidity. The stiffening rib 27 is centered between the two recesses holding the actuator members 25 and biasing springs 26 so as not to interfere with the movement of the movable contact arms 29a, 29b. The range of movement of the contact arms is defined by the switch contact positions in the modular block subassembly 30 (described in detail below). A pair of bumper posts 28 is fixed in the top housing part to act as a backstop and protect the moving parts from over-travel.
The modular block subassembly 30 has upright walls defining spaces to accommodate the pair of movable contact arms 29a, 29b and is seated in the central aperture 41 in the bottom housing part 40 to be encased between it and the top housing part 20. The modular block subassembly 30 (described in detail further below) is formed as a separate part from the other surrounding parts of the switch. The switch contact plates in the modular block subassembly are electrically connected to the terminal plates in the bottom housing part by any suitable means, such as by the clip portions 32a and 34a which are positioned on opposite lateral sides of the subassembly 30 receiving the respective tab portions 35a, 36b of the terminal plates 35 and 36. The terminal plates have wire clamp members (posts and screws) 42 for clamping the wire leads wired thereto. Another benefit of forming the terminal plates separately from the switch contact plates in the modular block subassembly is that over-torqueing of the screws when attaching the wire leads to the terminal plates does not cause any distortion to the switch contacts.
The pair of movable contact arms 29a, 29b have respective movable arm contacts 29a′, 29b′ on their lower ends which are moved in tandem between opposing switch contact positions in response to the up and down movement of the toggle member 21. The movable contact arms are seated in electrical contact with cradles 29c, 29d formed with respective cradle plate halves 29e, 29f. The cradle plate halves 29e, 29f have wire clamp members 44 for holding corresponding wire leads. The upper ends of the movable contact arms 29a, 29b are engaged with respective ones of the actuator members 25 of the toggle subassembly. Movement of the toggle member 21 pivots the actuator members 25 which turns the upper ends of the movable contact arms 29a, 29b, causing the movable arm contacts 29a′, 29b′ to swing from one switch contact position to the other in the modular block subassembly. The cradle plate halves 29e, 29f are shown in the drawing with ears 29g that extend upwardly through the floor of the top housing part to make electrical contact with light bulbs or LEDs to illuminate the switch, such as through translucent plastic material used to form the toggle member. The ears 29g and bulbs or LEDs are omitted in a non-illuminated switch.
The top and bottom housing parts may be joined together in several ways to form a sturdy switch unit. Hanging bosses on the lower surfaces of the top housing part 20 fit within walls 64 of the bottom housing part and can be ultrasonically welded thereto by positioning an ultrasonic horn along the walls of the rectangular cavity of the top housing part. The mated top and bottom housing parts are girdled in the rigid metal strap 60, and a pair of drive pins 62 are inserted through holes formed in the strap and in the bottom housing part 40 and have their ends fastened to fastener members 27a in the top housing part 20. The fastening method can be by threading in threaded fastener holes or press-fitting drive pin ends with zero-pitch threading. A wire clamp member (post and screw) 63 is formed on one side of the strap 60 for attaching a ground lead.
In
A bottom block member 54 is made of electrically insulative material for sandwiching the top switch contact plate 52 between it and the top block member 50 and electrically insulating it from the bottom switch contact plate 56. The bottom switch contact plate 56 is formed of electrically conductive material with a pair of upright, crossover tabs 57a, 57b having switch contacts 57a′, 57b′ thereon. A clip portion 32a is positioned on an opposite lateral side (left side of the drawing) of the block subassembly to connect the bottom switch contact plate 56 to a corresponding terminal plate by receiving the terminal plate tab therein. The switch contact tabs of the bottom switch contact plate 56 are inserted through slots 55a formed in the bottom block member 54 and through aligned slots 51d in the top block member 50 to be positioned at opposite switch contact positions in each of the hollow spaces 51a, 51b.
The bottom block member 54 has spaced stacking pins 55b on its upwardly facing surface that are inserted through aligned holes 51c in the top block member 50 and are ultrasonically welded. Other means of joining these block members together may be used, such as heat staking or gluing. The top and bottom block members may be molded from a high-quality, heat-resistant and insulative material, such as glass-filled Nylon. The rigid, high temperature material ensures safe operation of the switch subassembly. The design of the block subassembly in layers isolates critical tolerance parts from each other, thereby eliminating tolerance error stack-up.
The complete switch unit is assembled by seating the assembled modular block subassembly into the central aperture 41 of the bottom housing part 40 (see FIG. 2), then the switch contact terminal plates 35, 36 with wire clamp members 42 and the movable contact arms 29a, 29b coupled to cradle plates halves 29e, 29f with wire clamp members 44 are dropped into the side apertures 43 and 45, respectively. The top and bottom housing parts 20 and 40 are then assembled together, the strap 60 is positioned around the housing parts, and the drive pins 62 are pushed in through the holes in the strap and bottom housing part and fastened (press-fitted, threaded, welded, glued, etc.) to the fastener members 27a in the top housing part. The bumper posts 28 are pressed into place, then the toggle subassembly with member 21, actuator members 25 and springs 26 held therein is snap-fitted into the rectangular cavity in the top housing part. The modular “drop in” design of the switch parts and subassemblies allows the unit to be readily assembled through automation.
In the 4-way switch configuration shown, the switch contacts are positioned on opposite sides of the two switch contact pairs, so that pivoting the toggle member in one direction results in one cradle plate half being connected to one terminal plate then to the other terminal plate when the toggle member is pivoted the opposite way, and vice versa for the other cradle plate half. The switch contacts could instead be arranged without crossover tabs, but rather tabs on the same side of each switch contact pair, so that pivoting the toggle member in one direction connects both cradle plate halves to one terminal plate at the same time, and both cradle plate halves to the other terminal plate when the toggle member is pivoted the opposite way. The 4-way switch arrangement has a full complement of parts that permits it to be wired in various configurations including but not limited to, single pole, 3-way, double pole and 4-way.
Other switch configurations may be included in a whole product line using the same component parts except for changing the configuration of the switch contact plates and omitting any unnecessary parts. In
For the modular block subassembly, the top and bottom block members may be molded from high temperature plastic material and do not need to be changed for different switch configurations. Thus, the improved switch of the present invention can limit the costs of molding expensive insulative parts for a complete product line. Also, since the modular block assembly uses only one set of molded block members, and the same top and bottom housing parts, movable contact arms, terminal plates, contact arm plates, and rocker assembly are used for the different switch configurations, fabrication costs for the whole product line are reduced, and the problem of tolerance error stack-up is eliminated for the parts assembly.
In summary, the improved rocker-type switch is designed to be configured for different switch configurations of a product line by changing the configuration of the switch contact plate(s) in said modular block subassembly with minimal change to the surrounding parts. The block subassembly has a modular “drop in” design that facilitates ease of assembly and allows it to be performed through automation. The modular block subassembly and its encapsulation between the top and bottom housing parts also provide for substantial noise reduction in the electrical hum that can occur in the hollow bodies of conventional rocker-type switches. Also, the arrangement of the modular block subassembly provides an improved dielectric spacing between open electrical contacts, and eliminates distortion of contacts if a user exerts high torque when wiring electrical leads to the terminal wire clamp screws.
It is understood that one skilled in this field, given the described principles of the present invention, may make other modifications and variations, such as to the various switch components, assemblies, layouts, materials, and switch configurations described above. It is intended that all such modifications and variations be considered as within the spirit and scope of this invention, as defined in the following claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 3584163 | White | Jun 1971 | A |
| 3770820 | Pollak | Nov 1973 | A |
| 4123634 | Hults | Oct 1978 | A |
| 4638597 | Lybecker | Jan 1987 | A |
| 4843200 | Parlatore et al. | Jun 1989 | A |
| 5207317 | Bryde et al. | May 1993 | A |
| 5380972 | Lunak et al. | Jan 1995 | A |
| 5382768 | Kurek et al. | Jan 1995 | A |
| 5384441 | Balaban et al. | Jan 1995 | A |
| 5500498 | Kurek et al. | Mar 1996 | A |
| 5570778 | Gernhardt et al. | Nov 1996 | A |
| 5595289 | Kurek et al. | Jan 1997 | A |
| 5630502 | Kurek et al. | May 1997 | A |
| 5647479 | Gernhardt et al. | Jul 1997 | A |
| 5731559 | Daccord | Mar 1998 | A |
| 5749459 | Balaban et al. | May 1998 | A |
| 5826710 | Kurek et al. | Oct 1998 | A |
| 5836443 | Gernhardt et al. | Nov 1998 | A |
| 5865303 | Gernhardt et al. | Feb 1999 | A |
| 5934451 | Yu et al. | Aug 1999 | A |
| 5950812 | Tanacan et al. | Sep 1999 | A |
| 5990436 | Balaban et al. | Nov 1999 | A |
| 6339201 | Balaban et al. | Jan 2002 | B1 |
