US3280277A

US3280277A - Quick acting switch

Info

Publication number: US3280277A
Application number: US391473A
Authority: US
Inventors: Max L Jeffrey
Original assignee: R B DENISON Manufacturing CO
Current assignee: R B DENISON Manufacturing CO
Priority date: 1964-08-24
Filing date: 1964-08-24
Publication date: 1966-10-18
Anticipated expiration: 1983-10-18

Description

Oct. 18, 1966 M. JEFFREY 3,230,277

QUICK ACTING SWITCH v Filed Aug. 24, 1964 5 Sheets-Sheet 2 5 zz ZZ 6 24 INVENTOR MaXL. Jeffrq) BY 0. W

A6 3 ATTORNEY Oct. 18, 1966 M. L. JEFFREY 3,280,277

QUICK ACTING SWITCH Filed Aug. 24, 1964 5 Sheets-Sheet 5 INVENTOR Max" L. Jef'frey BY U. 04

# ATTORNEY United States Patent 3,280,277 QUICK ACTING SWITCH Max L. Jeffrey, Chagrin Falls, Ohio, assignor to R. B. Denison Manufacturing C0,,Bedford, Ohio Filed Aug. 24, 1964, Ser. No. 391,473

8 Claims. (Cl. 200-47) 1 This invention relates to switches and more particularly to a snap action switch of the general character of that shown-in my US. Patents 3,068,332 of December '11, 1962 and 2,807,685 of September 24, 1957. I

Switches of this general character are particularly useful in conjunction with electrically operated machines 4 as limit switches.- It is desirable in'such instances that they operate for long periods of time for many cycles. It is also desirable that they; be small so that they can -be installed in places where thereare space limitations Such switches should also be able to carry relatively large currents. a

One of the problems,-in the manufacture of switches of this character, is to provide one that is small and still will handle large currents. Another problem is to pro-.1 vide a switch which can operate over long periods with its operation. The'structure is also capable of high produc?.

tion manufacture since the manufacturing tolerance may be greater than normallyallowable in such switches, without degrading its operation. 7

A feature of the invention resides in the fact that the housing ismade in two halves and all of the parts may be quickly andeasily assembled withoutthe use of special tools. This also makes it convenient to service when and if service is required. The contacts are such that they can quickly and easily be removed and replaced, these being the parts normally wearing the most. By the present structure, a high degree of over travel of the operating means is realized, thus enabling the device to be operated in places where there maybe some variance in the travel of the operating member. In addition, althoughsmall, the open circuit gap is relatively large, reducing the tendency to arc. Because of its construction nearly all of its parts can be made of a non-corrosive material, such as one of the well known plastics.

Still other advantages of the invention, and the invention itself, will become more apparent from the following description of an embodimentthereof which-is illustrated by the accompanying drawings and forms a part of this specification.

In the drawings: i

FIG. 1 is an enlarged vertical medial section of a switch embodying the invention;

FIG. 2 is a section on the line 22 of FIG. 1;.

FIG. 2 is a section onthe line 22 of FIG. 1;

FIG. 3 is a section on'the lll113-30f FIG. 1;

FIG. 4 is an elevational view illustrating the inside of one ofthe housings with the contacts in place and a contact holder shown in section;

FIG. 5 is a section on the line 5-5 of FIG. 6

FIG. 6 is an elevational view of a rocker member, removed from the assembly;

.FIG. 7 is aview, partly in .elevation and partly in section, of the operating member;

:FIGS. 8 and,9 are plan and elevational views, respectively, of a movable contact member; and

' FIG. 10.35 a plan view, on a reduced scale, of a con tact positioning. member. r

Referring now tothe drawings, throughout which like partsare designated by like reference characters, and

particularly to FIGS. 1, 2 and 4, the housing which is .madeof a suitable molded plasticsuch as nylon, is made in'two halves lll'a, and 10b,which may be mirror images ofeach other. As can best be seen from FIG. 4, each housing half includes an outer shell including end walls 11, atop wall 12 and a, bottom ,wall 13 I .Inthe upper corners there are provided latch supporting bosses.15 and in the lower corners fixed contact supporting bosses .17, all of which may be molded integrally with the housing. .The upper bosses are provided with bores. 15a in .Which pawl support pins are disposed, as later described. I

The bottom bosses are provided with grooves which extend from the open side of the housing through to the side wall. 'In these grooves the fixed contact members are disposed and each, looking at the righthand side of FIG..4, includes a,contact.,20 supported on a contact strip which sets on top of the boss and extends over to the wall 11, thendownward at 22 and then backward at 23, and finally is provided with an end 24 which projects through a kerf in the bottom of the housing. The le'fthandfixed contact is similar in construction and it is supported in a similar groove but is spaced slightly from the other end wall. The projections 24 enable the device to be plugged into a suitable socket wired into the circuit to be controlled. v

The contact members may be slipped into the grooves from the open side of the housing. Once insertedthey are held in. place by an insulated plate 25, FIG. 10, which may be one of the linen reinforced phenolic resins, of general rectangular formation and provided with pairs of slots 26 on opposite sides. The depth of the slots is such that, after the contact strips are placed in position, the

, plate may then be placed in position and the walls of the slots telescope past the strips until the bottoms 26a of the slots engage with the edges of the contact strips and hold them in a fixed position. The end walls of the housing are provided with shallow grooves for the slidable reception of the ends of the plate.

Likewise, the other set of fixed contacts may be placed in the other housing half and, after the other parts about to be described are assembled in position, the other half of the housing assembled, with the first half, and the entire assembly held together by a bolt 30, FIG. 2. v v

As can best be seen from FIGS. 2 and 4, each housing half is provided with an inwardly extending U-shaped wallportion 31, which extends from the topto a point spaced from the bottom. The bottom is provided with a thickened bottom 32 having a slot 33 which enables, the housings to be mounted by bolts, not shown, to the machine or support for the switch.

On .the inside of each housing, the wall portion 31 is provided with a boss 34 which has a bore 35 through which the shank of the bolt 30 may extend, the head of the bolt seating in the bottom of the part 31 on one housing half and the nut in the other half. Thus, the securing means is disposed inwardly of the side walls.

The bosses 34 are provided with counterbores 36 which provide seats for the ends of a rocker support sleeve 38 which is telescoped around the bolt 30.

The rocker, which is pivotally supported on the sleeve 38 includes a base 40 having a pair of laterally extending bottom arms 41. Near their ends each arm is provided with a narrowed extremity 41a and spaced from each end there is an upwardly extending boss 41b. Extending upward from the base 40 is a stem 42, the upper end of which bears a pair of laterally extending arms 43 spaced above and opposite to the arms 41 and each having a downwardly extending boss 44.

The base 40 and stem 42 are cored to provide an upwardly extending socket 45, which extends from the bottom to a point spaced from the top. The base is provided with transversely extending openings 47 through the walls formed by the cored interior for the reception of the pivot sleeve 38, these openings being centrally of the stern and at the intersection of the top surfaces of the arms 41, which arms slant upwardly at a slight angle from the center line of the stem. A second set of smaller open ings 48 are provided through the stem walls for the reception of a spring keeper pin 49. A rocket actuating spring 50 of inverted U-shaped is disposed in the socket 45, the bight of the spring being held in the socket by the pin 49. The spring is preferably a laminated spring and has end portions which project below the bottom of the base 40.

As can best be seen from FIGS. 1 and 2, the rocker element carries the movable contacts and these make contact with the fixed contacts when the rocker is rocked. FIGS. 8 and 9 show plan and edge views of the movable contacts. Each set of movable contacts is in the form of a U-shaped plate 52 having rounded ends 52a which provide the contact surfaces. Along one side of the base there is a downwardly extending fulcrum member 52b and intermediate the legs on the base a pair of upwardly extending spring engaging lugs 52c. Each plate with its contacts is seated on top of the rocker surface with the fulcrum member 52]) adjacent the base of the stem 42 and with the legs bearing the contact surfaces 52a straddling the lug 411) which extends upward from the rocker. It is pointed out that separate contacts, indicated at 52x, could be secured to the arms, if desired. The contact plate is held in place on the top side of the rocker arms by helical springs 54 interposed between the supper arms 43 and the contact plate, the one end of each spring being positioned by the lug 44 under the upper arm and the other end around the lugs 520 on the upper surfaces of the contact plate.

Thus, the movable contacts are resiliently held to the rocker but can fulcrum and tilt about the member 52b when they engage with the fixed contacts. It will be noted that the member 5212 is of such a length that, together with the spring 54, which engages with the lugs 520, there is some. stabilization, thus assuring separation of both contacts on the break, and, short enough that it may tilt allowing the opposite contact arms to move to different levels to compensate for any inequalities of elevation of the fixed contacts. As best shown in FIG. 3, the two contact ends of the contact plate extend over the fixed contacts and when engaged therewith complete a circuit between the two fixed contacts on one end of the switch. Likewise when rocked the other way, the other two fixed contacts are connected together.

The rocker is rocked by a slide member which engages with the projecting ends of the spring 50. The slide, best shown in FIG. 7, consists of a rectangular body 55 having a notch 56 intermediate its ends into which the ends of the spring 50 project. One end of the slide is formed with a socket57 and a helical spring 58 is disposed in the socket with one end bearing against the end wall of the housing (FIG. 1) to urge the slide to the right. The other end of the slide is reduced to provide a cylindrical operating pin 59, which projects through a circular opening in the opposite end wall. Thus, the slide may be moved to the left against the pressure of the spring 58 and when released, returns to the position shown in FIG. 1.

The above is recited as an example of one mode of control. If desired, the spring could be omitted and the slide provided with a projection 592:, shown in dotted line, similar to that at 58, on the other end and thus the slide operated from either end and, in this instance, it would stay in the position to which it has been operated until the other end is pushed.

The rocker is held against rocking movement until a predetermined amount of pressure is built up in the spring 50 when it is then released and the spring snaps it quickly to the alternate position.

In order to effect the above operation, the slide is provided with a pair of spaced upwardly extending abutments. 55 and 55b. These are arranged to engage the ends 60a and 60b respectively of pawls 60. Each pawl has a base 61 which is journalled on a pin 62 mounted in the bosses 15. Since there are two bosses on each housing half, when the halves are assembled the pin is supported at both ends. The pawls each have a body or stem which extends downward opposite the ends of the lower rocker arms 41, and which is provided with a downwardly facing seat 64 arnanged to engage with the upper edge extremity of the rocker arm 41 (FIG. 1). The portions 60a and 60b of the pawls extend downward opposite to and arranged to be engaged by the abutments 55a and 55b on the slide 55. Coil springs are provided, each having a body 70 disposed around a spacer sleeve 62b adjacent the pawl and having an arm 70a engaging the housing wall and another arm 7% at the a other end of the spring hooked around the body of the pawl to urge each pawl toward the end of the rocker arm 41.

In operation, it being assumed that the parts are in the position shown in FIG. 1, where the movable contacts 0n the left have shorted the fixed contacts, it will be noted that the movable contact plate has been tilted about its fulcrum ledge 52b and that the spring between the

arms

43 and 41 of the rocker member has been compressed, holding the movable contacts securely against the fixed contacts at one end, the operating slide being at the right extremity of its travel. When the slide is :moved to the left, the right-hand face of the notch 56 engages with the adjacent leg of the spring 50 and moves that leg toward the center line of the socket 45. At this time the slide return spring 58 is being compressed. As soon as the gap between the slide lug 55a and the pawl extension 60a is closed, continued movement of the slide starts swinging the pawl clockwise against the pressure of the pawl spring '70. It is pointed out that this could be a helical spring extending between the housing wall and the pawl, if desired.

It will be noted that the contact face of the abutment 55b (as well as 55a) is curved. This curvature is such that the engagement of the pawl with the abutment surfaces is of a rolling character, the surface 55a always having a tangential engagement with the pawl surface when it is moving the pawl. The curvature may be on a radius which is equal to the distance from the pivot center of pawl support pin 62 to the end 60b of the pawl.

This promotes -a smooth, easy action and longer life because there is a minimum of sliding action and thus friction between the parts is reduced.

As the pawl is moved, the stored energy in the spring 50 is increased and the force on the rocker in a clockwise direction, due to the distortion of the spring 50, is increased. The seat 64 on the pawl. gradually slides outward toward the end of the rocker arm until finally it slides off the end of the rocker arm and the rocker is released.

When the operating slide has been finally pushed to the left to the point where the 'pawl is released, there to its alternate position.

The first portion of the clockwise movement of the rocker arm causes the left side to be raised between the fixed contacts but the spring 54 causes the movable contact plate to rotate about its fulcrum ledge 52b, holding the movable contacts against the fixed contacts until the gap between the bottom of, the movable contact plate and the rocker arm, adjacent the lugs 41b, is closed. Although this closing of the gap is relatively quick and the relative movement between the movable contact plate and the rocker arm is not very large, it does provide an increment of time lag before the opening of the contacts, whereby the inertia of the rocker arm is well on its way to maximum, thus causing the rocker arm to strike the contact plate with a blow. This decreases the opening time of the contacts and there is a decrease in the arcing time due to the fact that when the contacts open, they open quickly.

As the right end of the rocker comes down, the right movable contact is held in the position shown against the top of the rocker arm until the ends of the movable contacts engage with the fixed contacts. Then the movable contact plate rotates about its fulcrum ledge 52b and finally comes to rest in the position the same as was taken by the left-hand contact, as shown in FIG. 1.

A peculiarity of this construction is that the contact is made before the rocker reaches the end of its travel and although the rocker may bounce because there may be a clearance between the bottom side of the rocker arm and the abutment 17, which extends under the rocker arm, there is substantially no bounce to the contact because the main weight of the contact plate is adjacent the stem 42 of the rocker and the spring 54 holds the contact plate with its lighter outer ends against the fixed contacts and the movable contact may move relative to the rocker but does not bounce off the fixed contacts.

When the rocker arm finally reaches the end of its travel, it is locked in position by the pawl snapping over the end of the arm, as shown at the left of FIG. 1.

It is important to note that because of this construction the manufacturing tolerances may be larger than ordinarily without any sacrifice in the operating characteristic. Furthermore, the construction enables nearly all of the parts, except the contacts, springs and support pins, to be made of molded plastic which provides a smooth operation, reduces the need for lubrication, and, is long wearing.

As can best be seen from FIG. 3, friction of the slide member 55 with the guiding portions of the bosses 17 is reduced to a minimum by providing a relief on the side of the bosses toward the slide and by a ridge extending along the bottom of the slide. This, coupled with the fact that the parts except for the pivot pins and contacts may all be made of plastic such as nylon, provide an easy operating mechanism.

It will also be noticed that the design of the slide and the latches is such that, when the spring 58 is not used, the same springs that hold the latches in engagement with the rocker also resist accidental movement of the slide, thus holding it in its alternate position.

Having thus described the invention in an embodiment thereof, I am aware that numerous and extensive departures may be made therefrom without departing from the spirit or scope of the invention as defined in the appended claims.

I claim:

1. A switch comprising a support, a rocker member pivotally mounted on the support and having first and second pairs of arms and a central stem disposed between said arms and holding them in spaced relation to each other, movable contact members carried by said rocker member, said rocker member having contact positioning members on each arm of the first pair of arms extending toward each arm of said'second pair of arms and a movable contact member being seated on each of said first arms in guided engagement with said positioning members and positioned between said stem and said positioning members, spring means extending between said contact members and the second armsand'holding said contact members resiliently on first arms, fixed contacts carried by the support and di sposedopposite said movable con- I met members, said rocker member arranged to rotate said arms beyond the plane of said fixed contacts, said movable contact members each being arranged to engage with the fixed contacts and to move on said first arms to tilt said movable contact member against the pressure of said spring after engagement with the fixed contacts.

2. A switch as described in claim 1, wherein fulcrum means is provided on each of said movable contact members to provide a transversely extending fulcrum therefor disposed in contact with each of said first arms.

3. A switch including a housing, a tiltable rocker member pivotally supported in said housing and having limited tilting movement in opposite directions and comprising a stem portion, upper and lower rocker arms extending laterally in opposite directions from said stem portion, movable contact means, said lower arms formed to provide a seat for said contact means and having guide means thereon positioning and guiding said contact means, spring means engaged between said contact means and said upper arms holding said contact means resiliently pressed against the seats, fixed contacts supported at opposite ends of said rocker arms at a level such that when the rocker member is tilted the movable contacts engage therewith prior to the completion of the tilting movement of the rocker member, means to tilt said rocker member in alternate opposite directions comprising movable means supported by the housing below the rocker member, and spring means connected to the rocker member and engaged by said movable means, means to hold said rocker member against tilting comprising latch means disposed at each end of said lower rocker arms, spring means for urging said latches toward the ends of said rocker arms and means on said movable tilt means alternately engageable with said latches to release said latches upon a predetermined amount of movement of said tilt means.

4. A switch as described in claim 3, wherein the stem of said rocker member is formed with a recess and said spring means is held in said recess with portions thereof extending out of the rocker member into engagement with said movable means.

5. A switch as described in claim 3, wherein said latch engaging means comprises abutments on said tilt means, each abutment having a curved surface facing toward the end part of said latch, the curvature of said surface providing a rolling engagement with the latch surface.

6. A switch comprising a housing of box-like form comprised of two parts each of which is a mirror image of the other, each of said housing parts being formed to provide an inwardly extending boss at its longitudinal mid-section, pairs of fixed contacts supported by said housing at each end, pivot means extending between said bosses and a rocker member disposed on said pivot means, said rocker member comprising a pair of lower arms arranged to pass between said fixed contacts, a second pair of arms on said rocker member disposed above said lower arms in spaced relation thereto and movable contact positioning lugs near the ends, movable contact members supported by said lower arms and comprising U- shaped members straddling said positioning lugs, spring means engaged with the upper arms and the top of said movable contact member, said fixed contacts being supported at a level such that when the rocker member moves said moveable contact members into engagement '7 with the fixed contacts, the outer end of the movable Contact members is moved away from the rocker member.

7. A switch as described in claim 3, wherein said rocker tilting means comprises an elongated member reciprocably journalled in the housing below the rocker member and formed with an extension extending beyond the confines of the housing.

8. A switch as described in claim 7, wherein said tilting means is formed with a recess and spring means is disposed in the recess and in engagement with the housing wall to hold the tilting means in a predetermined position.

References Cited by the Examiner UNITED STATES PATENTS Bradstock et al. 20070 Benander 200-1 66 Wright 200-166 Scribner 200-104 X Scheib 200104 m BERNARD A. GILHEANY, Primary Examiner.

T. D. MACBLAIN, Assistant Examiner.

Claims

1. A SWITCH COMPRISING A SUPPORT, A ROCKET MEMBER PIVOTALLY MOUNTED ON THE SUPPORT AND HAVING FIRST AND SECOND PAIRS OF ARMS AND A CENTRAL STEM DISPOSED BETWEEN SAID ARMS AND HOLDING THEM IN SPACED RELATION TO EACH OTHER, MOVABLE CONTACT MEMBERS CARRIED BY SAID ROCKER MEMBER, SAID ROCKET MEMBER HAVING CONTACT POSITIONING MEMBERS ON EACH ARM OF THE FIRST PAIR OF ARMS EXTENDING TOWARD EACH ARM OF SAID SECOND PAIR OF ARMS AND A MOVABLE CONTACT MEMBER BEING SEATED ON EACH OF SAID FIRST ARMS IN GUIDED ENGAGEMENT WITH SAID POSITIONING MEMBERS AND POSITIONED BETWEEN SAID STEM AND SAID POSITIONING MEMBERS, SPRING MEANS EXTENDING BETWEEN SAID CONTACT MEMBERS AND THE SECOND ARMS AND HOLDING SAID CONTACT MEMBERS RESILIENTLY ON FIRST ARMS, FIXED CONTACTS CARRIED BY THE SUPPORT AND DISPOSED OPPOSITE SAID MOVABLE CONTACT MEMBERS, SAID ROCKER MEMBER ARRANGED TO ROTATE SAID ARMS BEYOND THE PLANE OF SAID FIXED CONTACTS, SAID MOVABLE CONTACT MEMBERS EACH BEING ARRANGED TO ENGAGE WITH THE FIXED CONTACTS AND TO MOVE ON SAID FIRST ARMS TO TILT SAID MOVABLE CONTACT MEMBER AGAINST THE PRESSURE OF SAID SPRING AFTER ENGAGEMENT WITH THE FIXED CONTACTS.