US3390243A

US3390243A - Multiple switch assembly

Info

Publication number: US3390243A
Application number: US664080A
Authority: US
Inventors: Obermann George
Original assignee: Controls Company of America
Current assignee: Controls Company of America
Priority date: 1967-04-17
Filing date: 1967-08-29
Publication date: 1968-06-25
Anticipated expiration: 1985-06-25
Also published as: GB1212069A; NL6805353A; DE1765184B2; DE1765184A1; FR1560850A; US3431372A; DE1765184C3; JPS503876B1; GB1212070A; JPS5219672B1; DE1790340A1; ES352793A1

Description

J1me 1968 G. OBERMANN MULTIPLE SWITCH ASSEMBLY 5 Sheets-Sheet 1 Original Filed April 17, 1967 June 25, 1968 G. OBERMANN MULTIPLE SWITCH ASSEMBLY Original Filed April 17 1967 5 Sheets-Sheet 2 Jun 25, 1968 G. QBERMANN MULTIPLE SWITCH ASSEMBLY Original File a April 17,1967

5 Sheets-Sheet 4 June 25, 1968 G. OBERMANN MULTI PLE SWITCH ASSEMBLY 5 Sheets-Sheet 5 @d/V 26 4 M j M Z4 /ZZ J y/M' m FR United States Patent Claims. (Cl. 200-166) ABSTRACT OF THE DISCLOSURE The switch blades are molded into wafers which can be stacked to provide an assembly having grouped terminals for a suitable connector cable. Selected blades can be interconnected by a variety of bussing methods. The active blade end engages a guided follower which rides on the cam and is not sensitive to direction of rotation of the cam. The passive blades abut stops in the follower guide to eliminate need for adjustment. Axial movement of the cam arbor actuates a line switch in one of the switch assemblies. A drive cam can actuate another switch which can also be actuated by the main cam. The cam arbor is mounted between end plates spaced by the motor mounting plate and the motor bearing is free of radial loading.

Cross-references to related applications This is a division of application Ser. No. 631,371, filed Apr. 17, 1967.

Background of invention This invention relates to timers of the type used in programming washing machines and the like. The accepted form of such a timer utilizes a rotary cam which actuates switches, each having the active blade formed to ride on the cam. The switches generally required adjusting after completion of the assembly of the timer and this adjusting could affect the actual point of contact with the cam and, hence, slightly change the timing sequence. This becomes of some importance when it is realized that when the cam is stepped it is often desired to axially sequence operation of the switches within the time it takes to step the cam one step. The prior art arrangement also resulted in terminals being arranged over a large area and usually on more than one side of the timer making simple wiring connections virtually impossible and, hence, the time required for installation in the washing machine was longer than desirable. Separate hand wiring was required for interconnecting various blades. The designs have been limited to having the manual knob shaft extend in only one direction and frequently loaded the motor bearings.

Summary of invention This invention is directed to the simplification of manufacture, assembly, and installation of timers while at the same time reducing the size and increasing the reliability of the product. This has been accomplished in various ways. The cam arbor is journaled between end plates in such a way that the arbor provides its own hearing while being isolated from lateral loading which could result in misalignment. The drive is mounted to eliminate loading of the motor bearings.

Possibly the most significant area of improvement is the manner in which the various switch assemblies are built up. Each switch assembly includes three wafers and each wafer includes the blades assigned to that wafer molded into a plastic block. The portion of the blades within the block is provided with a configuration providing, where desired, suitable tabs which align with cooperating holes in the wafers. When the wafers are as- 3,3%,Z43 Patented June 25, 1968 sembled into a single block all the holes are aligned. This makes possible bussing between selected blades in different vertical alignments or in the same alignment simply by stabbing through the openings with a connector to engage the projecting tabs. This simple method of bussing lends itself to automated production and avoids most of the previously required separate wiring connections. The switch assembly is designed to have the active blade in the middle wafer and the end of this blade projects into a guided follower which rides on the periphery of the selected cam. The follower itself is guided for movement normal with respect to the cam and, hence, is precisely positioned and is not limited to a single direction of cam movement with respect to it so all terminals can now face one direction even though assemblies are positioned on opposite sides of the cam. The passive blades in each switch assembly rest on stops on the follower guide and these stops serve to accurately position the passive blade ends. With this assembly there is no need whatsoever for adjustment and yet a higher degree of accuracy is obtained.

Since not all of the switching functions desired in a timer are derived from the cam, provision is made for actuating the so-called line switch upon axial movement of the manual shaft by camming a suitably positioned sliding link which acts directly on the line switch in one of the switch assemblies. There is also provision for overriding the cam directed action of another switch (usually a water valve switch) by means of a linkage operated by the drive cam assembly to provide subinterval switching or spray rinse function.

The invention is shown in connection with a drumtype cam but is readily adapted to a disc-type cam.

Description of drawings FIG. 1 is a partial exploded perspective view giving the general orientation of the parts;

FIG. 2 is a simplified showing of the drive mechanism together with the subinterval switch arrangement;

FIG. 3 is similar to FIG. 2 but shows the subinterval switch mechanism in its inactive position and the switch under control of the main cam;

FIG. 4 is a simplified exploded view of a switch as sembly;

FIG. 5 is an enlarged detail view of a typical bussing arrangement for the single throw blade wafer, that is the upper wafer of the assembly;

FIG. 6 shows the active or middle wafer typical arrangement;

FIG. 7 is the lower or double throw wafer typical bussing arrangement;

FIG. 8 is a representative plan view of an assembly showing various bussing arrangements;

FIG. 9 is a section taken on the meandering section line 9-9 of FIG. 8 to show the various bussing arrangements;

FIG. 10 is a perspective view of the inter-row bussing clip;

FIG. 11 shows the way in which a terminal can be connected to one of the wafers;

FIG. 12 shows the intra-wafer bussing;

FIG. 13 is a fragmentary enlarged perspective view of the follower guide block;

FIG. 14 is a simple showing of the manner in which the follower is guided in the guide block which supports the ends of the passive blades;

FIG. 15 is comparable to FIG. 14 but shows the active blade in the middle position not contacting either the double or single throw blade;

FIG. 16 shows the single throw action;

FIG. 17 shows the manner in which the axial motion of the timer shaft is transferred to the line switch; and

FIG. 18 is an end view of the arbor giving a better understanding of the construction of the line switch disc and the shaft to cam drive.

Description preferred embodiment The main timing cam is mounted between front plate 12 and rear plate 14. The cam 10 is an integral molding with a central shaft 16 having a reduced end which is piloted in bushing 18 mounted in the front plate. The other end of the cam has a projecting shaft portion which projects through the cooperating hole in the rear plate with the end of the cam shaft being suitably slotted to receive the webs 20 of the line switch operating disc 22 carried by plastic hub 24 which has two peripheral grooves in either of which the detent spring 26 may rest. The plastic hub 24 is rigidly fixed on shaft 28 which projects through the cam and out the front plate 12 for mounting of a suitable actuating knob. Shaft 28 could project from the other end, which may be desired in some cases. The circular portion of the detent spring 26 seats against the inside face of the rear plate 14 and the shaft can be moved from the position shown in FIG. 17 to a more rearward position in which the spring 26 seats in the other peripheral groove on the hub 24. In both positions the shaft is drivingly connected to the cam through the webs 20. This, of course, moves the operating disc 22 rearwardly and as a result the slider 30 having cam face 32 engaging the disc 22 can move inwardly under influence of the inherent spring force in the active blade 34 acting through its follower 148. In the position shown in FIG. 17 the active blade has been moved into contact with the cooperating single throw blade 36. Thus when the knob is pushed in, the circuit through

blades

34, 36 is broken and when the knob is pulled out, the circuit is made. This switching function accommodates the so-called line switch function and at this point the detail mounting of the blades per se will be put off.

It will be noted that one end of spring 38 coiled around bushing 18 bears against post 40 while the other end bears against the upstanding car 42 carried by cam follower lever 44 to bias the free end against stepping cam 46. This cam is part of a molded piece which includes gear 48 driven by the motor pinion 50. The motor pinion, of course, is driven by motor 52 through suitable reduction gearing. In the view shown in FIG. 2 the follower portion of lever 44 has just completed the drop down the face of the cam to move pawl 52 pivoted on pin 54 on follower 44 forward to the point where it engages a stop carried by the anti-backup pawl 56. Both are seated on the same tooth at the completion of an indexing step. The advantage of this construction is more fully explained in copending application Ser. No. 504,910. Both pawls are biased into engagement with the ratchet teeth on the cam drum periphery by means of spring 58.

Indexing cam 46 and its associated gear 48 are mounted between plate 12 and the facing surface of motor mounting bracket 60 which has a plate portion 62 which acts to space the front and

rear plates

12, 14. The cam and gear member also includes a peripheral skirt-like cam portion 64 having various cutout portions into which follower 66 of link 68 pivoted at 70 may drop. The other end of the link carries an insulated portion 72 which underlies a laterally projecting finger on guided follower 146 to act on the finger to lift the follower and, hence, the active blade 76 when follower 66 rides on skirt 64. As will appear more fully hereinafter, the follower 146 can also be actuated by the cam 80 of the main cam on which it rides. This can happen only when the follower 66 can drop into a cutout in the skirt 64.

Up to this point reference has been made to active and passive switch blades and at this point the general construction features of the switch assemblies may be considered. While the unit shown in FIG. 4 does not have an exact counterpart in the actual timer shown it serves to simply show the general features. The active blades are carried by the assembly A. The ends of these blades are adapted to project into the guided followers as will appear more fully hereinafter. These are the blades which are actuated and they are molded into a plastic block or wafer holding the meandering portion of the blades in proper position and having a series of openings generally aligned with each blade. Before the molding actually takes place these blades are interconnected by webbing, the typical blade configuration in the wafer portion being shown in FIG. 6. The interconnecting web W may be left in place or may be sheared out by punching through the aligned hole after the molding is completed as shown in FIG. 12 where the webbing has been punched out at hole 102 but the webbing has been left intact at the next adjacent hole 104. This, then, is a simple method of interconnecting the two blades. This is one of the versatile features of this design.

The blades above the active blades A are the single throw blades B in FIG. 4. These blades have a typical root or proximal portion as shown in FIG. 5. The double throw blade assembly C has a typical root configuration as shown in FIG. 7. It will be understood that in each wafer there is a web portion W which may or may not be trimmed out after the molding of the wafer is completed. FIGS. 5, 6, and 7 are shown in general parallel alignment to better visualize the manner in which the wafers are stacked. It will be noted that in the portion of the blades molded into the wafer there are three distinct zones in each instance. These zones, for convenience, will be referred to as X, Y, and Z. On the single throw blades (which will be the upper wafer) in zone X there are punched out holes 106 into which the tabs 108 project. A similar arrangement is employed in zone X on the double throw blade while on the active blade the space which will align with the holes in the single and double throw blades and which is designated 110 on FIG. 6 is merely a void. Therefore, when these blades are stacked and the cooperating holes are molded into the wafers the single throw and double throw blades can be interconnected by driving a buss member through the cooperating holes to engage the tabs 108 in the top and bottom wafers of the assembly.

Now reference may be had to zone Y and here it will be noted that each active blade is provided with a hole 112 into which the tab 114 projects while the double throw blade is provided with a cooperating hole 116 into which the tab 118 projects. The single throw blade in this zone Y has a void 120 which will align with the

holes

112, 116 in the other blades. This, therefore, makes possible interconnecting the active and double throw blades by driving a buss through the aligned holes.

In the Z zone it will be noted that each blade is provided with an aperture 122 and tab 124 permitting bussing through all of these in the Z zone.

This concept can be carried forward in an assembly shown in plan view in FIG. 8 and in cross section in FIG. 9. This gives some idea of the versatility of the present design by way of freedom of interconnection of various blades. Bear in mind the section line on FIG. 8 is a meandering line which passes through the different zones. Going from the terminal end of the blades, the first row of horizontal holes affords access to the webbing W interconnecting the various blades and it is through these holes that the webbing is trimmed when it is desired to separate adjacent blades as would be most normal. The next row back is the Z zone followed by the Y zone and then the X zone. In FIG. 9 refer first to the buss 126 which is driven through the vertically aligned holes in the X zone. Therefore, in accordance with the principles discussed above, this buss 126 can only engage the single throw blade and the double throw blade but cannot connect to the active blade. Thus the top blade is connected to the bottom blade very simply. Now, then, refer to buss 128. This buss has been pressed into the assembly in the Z zone and if pressed far enough would obviously engage all three blades but this would rule out any possible utility so the buss is made short enough to reach only into the middle wafer and thus connect the top or single throw blade with the active blade. Now refer to buss 130 which appears best in FIG. 10. This buss member in plan view is in the nature of a U-shaped clip but has depending

legs

132, 134. Leg 132 is pressed into the Y zone and, in accordance with the principles above, we know that there is a void in the Y zone in the upper single throw wafer. Therefore, no connection is made here. The leg is made only long enough to pass through the second or middle wafer where it can make connection to the active blade. The other leg 134 projects into the Z zone where all the blades have aligned holes with cooperating tabs but since the leg 134 is only long enough to project into the upper wafer it connects only to the upper blade. With the U-shaped buss 130 we have now connected the upper blade (with leg 134) in one row to the active blade in another row (through leg 132). Thus with this type of buss it is possible to very readily interconnect different wafers with different rows, etc.

It will be noted that all the buss members are slightly thicker than the normal clearance between the hole and the tab projecting into the hole in the blade. Therefore, the tab is bent down as the buss enters the hole and acts as a locking device preventing withdrawal while insuring good electrical connection.

Just by way of illustrating another type of connection which may be used, FIG. 11 shows a male terminal 136 having in this fragmentary view a buss portion 138 passing through the upper wafer and engaging in the active wafer with the ramp 140 formed on the end of the buss locking under the tab to prevent withdrawal of the terminal. Thus when a female terminal is mounted on the male and later disconnected it will not pull the terminal from the assembly.

The versatility afforded by this type of arrangement should readily be apparent. It will also be appreciated that all of the desired terminal ends are brought out of one side of the final assembly where they appear in heat vertical and horizontal rows readily permitting connection to a plug assembly cont-aining'the wiring harness.

Now, then, going back to the active blades, it will be noted that in each case the active blade has a narrow projecting tip which is designated 142. Also note that the active blade 'is longer than the single or double throw blades. This allows the tip portion of the blade to project into the aperture 144 in guided follower 146. The protruding end 148 of the follower rides on the cam contour. The edges of the follower 146 are received in and guided by vertical grooves 150 in the guide block 152 fixed between the end plates with the portion 154 projecting from the ends of the guide block mounted in suitable apertures in each of the end plates to positively position the guide block so that it is positively oriented with respect to the main cam and, hence, the followers 158 are positively oriented with respect to the cams upon which they will ride. All the active blades are formed to be selfbiased downwardly so that the followers 148 are biased by the active blades to ride on the cam.

Each single throw blade 156 projects toward the guide block to overlie and rest the upwardly facing stops 158. Since the single throw blades are also initially bent downwardly they are self-biased firmly against these stops. The double throw blades are of suflicient length to underlie the lower stop surfaces 160, also formed on the guide block assembly. These blades are bent upwardly so that they also are self-biased to their stops.

Thus the active blades pass between the positively located upper and lower (or single and double throw) blades to engage and bias downwardly the vertically slidable followers which ride on the cam. The normal or open position is shown in FIG. 15 where the active blade is positioned by the cam surface between the single and double throw blades and, therefore, no circuit is made.

In FIG. 14 the follower has moved (under the blade bias) onto the lower cam surface and the active blade has moved into contact with the double throw blade 164. Assuming the self-bias of the active blade to be stronger than the self-bias of the double throw blade, the double throw blade will be moved downwardly ofi? its stop surface 160. If the converse is true of the bias of the blades the active blade would stop movement upon contacting the lower blade. It will be appreciated that abundant self-bias can be employed in these blades and this will result in excellent contact pressures. There is also a distinct wiping action between the contacts which helps break any welds that may occur.

In FIG. 16 the cam has lifted the follower and the active blade to complete a circuit through the active blade and the double throw blade. Some overtravel is desirable here to insure good contact pressure and wiping action between the contacts.

It is to be noted that the followers 148 are guided by the guide block to substantially radial action with respect to the main cam drum. For this reason the direction of approach of the cam relative to the follower has no effect and now the upper and lower blade assemblies can be positioned to position all terminals at one side of the timer. This means wiring clearance need be provided in the appliance on only one side of the timer with a significant space saving.

Another feature which should be noted is that since the main cam is rotatably mounted in the rather rugged stub shaft 18 there can be no transferral of radial loads from the drive mechanism to the main cam or to the motor bearing.

What is claimed is:

1. An electric switch including,

(A) a plurality of stacked insulating wafers,

(B) a plurality of spaced parallel blades in each wafer in vertical alignment with the blades of the adjacent wafer,

(a) the proximal portion of the blades being embedded in the associated wafer, (b) each wafer having holes therein in alignment with portions of each blade,

(i) the holes in wafers being aligned,

(C) a buss positioned in some of the holes to interconnect selected blades.

2. The switch apparatus of claim 1 in which the proximal portion of each of the blades connected by the buss includes a hole therein in alignment with the wafer hole through which the buss passes,

and a tab portion projecting into each blade hole and providing less clearance than required by the buss whereby insertion of the buss deflects the tab and the resiliency of the tab holds the buss in position.

3. A switch assembly according to claim 2 in which there are three wafers and the hole arrangement in each wafer and the configuration of the proximal portions of the blades permits selective connection by said buss to any blade in any wafer and to any two vertically aligned blades.

4. A switch assembly according to claim 3 in which the buss includes two interconnected probes each of which projects into diiferent holes of the wafer stack to connect blades which are not vertically aligned.

5. A switch assembly according to claim 1 in which some of the adjacent blades in a wafer are connected by a web.

References Cited UNITED STATES PATENTS 2,591,684 4/1952 Deakin ZOO-166.1 3,297,850 1/1967 Peek et al. 200-1661 3,356,802 12/1967 Simon 200-1661 ROBERT K. SCHAEFER, Primary Examiner.

HERMAN O. JONES, Assistant Examiner.