US3866002A

US3866002A - Dual-function line switch for a cam-actuated timer switch

Info

Publication number: US3866002A
Application number: US406680A
Authority: US
Inventors: David W Underwood; Benjamin F Chestnut
Original assignee: PR Mallory and Co Inc
Current assignee: Duracell Inc USA; Emerson Electric Co
Priority date: 1973-10-15
Filing date: 1973-10-15
Publication date: 1975-02-11
Anticipated expiration: 1992-02-11

Abstract

A cam-actuated timer switch includes a dual-function line switch responsive to axial movement of a cam shaft and also to rotation of an independent cam track. The dual-function line switch switches power from a power supply to the timer switch. Included in an embodiment of the invention are a ramping means to move the cam shaft axially at predetermined points during its rotation and a stop means to produce resistance to turning of the cam shaft at preselected points during its rotation.

Description

United States Patent 1191 Underwood et al.

[H1 3,866,002 1451 Feb. 11,1975

[54] DUAL-FUNCTION LINE SWITCH FOR A CAM-ACTUATED TIMER SWITCH [75] Inventors: David W. Underwood, Clayton;

Benjamin F. Chestnut, Greenwood, both of Ind.

[73] Assignee: P. R. Mallory & Co. Inc.,

' Indianapolis, Ind.

[22] Filed: Oct. 15, `1973 [21] Appl. No.: 406,680

[52] U.S. Cl. 200/33 R, 200/38 R, 200/38 A, 200/38 B, 200/38 C, 200/153 L [5 l] Int. Cl. H01h 43/10 [58] Field of Search... 200/35 R, 37 R, 37 A, 38 R, 200/38 A, 38 B, 38 BA, 38 C, 38 CA, 39 R, 153 L, 153 LA, 153 LB, 33 R [56] References Cited UNITED STATES PATENTS 2,920,153 l/1960 Horstmann 200/153 L X 3,025,366 3/1962 Woolley 200/38 C 3,053,947 9/1962 Bowman et al. 200/38 C 3,060,288 10/1962 Gallagher et al 200/38 C 3,417,211 12/1968 Wiser 200/38 R 3,581,028 5/1971 Valbona 200/38 R 3,582,582 6/1971 Pauker 200/38 B 3,737,595 6/1973 Simmons 200/38 R X Primary Examiner-.lames R. Scott Attorney, Agent, or Firm-Charles W. Hoffmann; Robert F. Meyer; Donald W. Hanson [57] ABSTRACT A cam-actuated timer switch includes a dual-function line switch responsive to axial movement of a cam shaft and also to rotation of an independent cam track. The dual-function line switch switches power from a power supply to the timer switch. Included in an embodiment of the invention are a ramping means to move the cam shaft axially at predetermined points during its rotation and a stop means to produce resistance to turning of the cam shaft at preselected points during its rotation.

7 Claims, 8 Drawing Figures DUAL-FUNCTION LINE SWITCH FOR A CAM-ACTUATED TIMER SWITCH Generally speaking, the present invention relates to an improvement to a cam-actuated timer switch having a housing means, a cam means rotatably carried on a shaft within the housing means and having independent cam tracks, switch means responsive to the cam means, and a drive means carried by the housing means driving the cam means, wherein the improvement comprises a line switch means `responsive to axial movement of the cam shaft and also to rotation of one of the independent cam tracks.

Line switches utilized for switching the main power to cam-actuated timer switches are well known in the art. A common form of a line switch in a cam-actuated timer switch includes a fixed blade having an electrical contact and a flexible blade also having an electrical contact. The flexible blade is responsive to in and out" indexing of a cam stack, so that the contacts either make or break for one of the indexed positions. A specific example can be found on a clothes washing machine timer wherein the shaft is indexed out to make the contacts and provide the timer and machine with power..

In many cam-actuated timer switches, a line switch is actuated directly by the face of one of the cams in an indexable cam stack. In such timer switches, elect-rical lswitches are responsive to cam surfaces on the peripheries of each of the cams. It is desirous in some cases to include a bypass switching function in these timer switches to bypass the line switch during certain parts of the timer cycle. Heretofore, this was accomplished by using one cam and one of the electrical switches in combination with the line switch.

The present invention provides for an additional switching function, such as a bypass, to be also carried out by the line switch. This makes the line switch a dual-function switch. As utilized in a timer with a face cam having a plurality of concentric cam tracks disposed on a face and a cam shaft axially indexable independent ofthe cam, the line switch of the present invention is responsive not only to an indexing in" and out of the cam shaft, but also to rotation of one of the concentric tracks. The result of this dual function of the line switch is the elimination of a relatively expensive set of switch blades and contacts.

The present invention may incorporate other features such as an additional line switch member and positive and overriding stops. The additional line switch member may comprise a double upper blade having electrical contacts and interposed between an actuator switch blade and an indexable switch blade of a line switch. The contact on the double upper blade engages contacts on the other two blades of the line switch. The result is an addition of a third electrical switching function to the line switch of the present invention.

Positive and overriding stops provide for easy and accurate manual setting of a cam-actuated timer switch. It is a well known problem in timer switches that time values are often difficult to set accurately because of the eye-hand coordination required to line'up an indicator on a manually set shaft with a specific division on a corresponding scale. Stops provide a definite interference to a manual turning of the shaft at those precise points where timing cycles are to be set, such as the beginning of a wash cycle. All the operator of a timer has to do is rotate the shaft, even without looking at the scale, until resistance is felt, whereupon he knows the correct setting has been reached. ln the case of a positive stop, the operator must index the shaft by pulling it out or pushing it in before turning past the stop if he so desires. In the case of an overriding stop, if the operator chooses to rotate the shaft beyond a stop, he merely applies additional turning torque to override the bump and continues to rotate the shaft. Embodiments of the present invention provide for positive and overriding stops in combination with the dual-function line switch to achieve heretofore unattained switching and setting combinations in a cam-actuated timer switch.

Accordingly, it is a feature of the present invention to provide an improvement to a cam-actuated timer switch wherein a line switch means is responsive to axially indexed translation of a cam shaft and also to rotation of a cam track of a cam means. Another feature of the present invention is to provide an improvement to a cam-actuated timer switch wherein a line switch means includes an axially indexable contact-carrying switch blade carried by a housing means and engaging an index disc carried by the cam shaft. Another feature of the present invention is to provide an improvement to a cam-actuated timer switch wherein a contactcarrying actuator switch blade carried by a housing means engages a contact-carrying indexable switch blade so that electrical connection is made through contacts in the blades. Still another feature of the present invention is to provide an improvement to a camactuated timer switch including a two-position index location means carried by a housing and engaging an axially indexable cam shaft to provide the cam shaft with two positions in spaced relation to the housing means. Yet another feature of the present invention is to provide an improvement to a cam-actuated timer switch including a stop means providing resistance to manually turning of a cam shaft to facilitate accurate setting of the cam shaft. Another feature of the present invention is to provide an improvement to a camactuated timer switch including a rigid stop member to positively stop manual rotation of a cam shaft at preselected points. Another feature of the present invention is to provide an improvement to a cam-actuated timer switch including an overriding stop function to provide torque resistance to manual rotation of a cam shaft at preselected points. Another feature of the present invention is to provide an improvement to a camactuated timer switch including a contact-carrying double-upper switch blade carried by a housing and electrically cooperative with a line switch means.

These and other features will become more apparent from the following description taken in conjunction with the accompanying drawings wherein:

FIG. l is an exploded pictorial view of a camactuated timer switch.

FIG. 2 is a top elevation view of an overriding stop version of a stop means.

FIG. 3 is a top elevation view of a positive stop version of a stop means.

FIGS. 4, 5, 6, 7 and 8 are partial diagrammatic sectional views ofthe cam-actuated timer switch showing different working positions of various components within the timer.

Referring now to FIG. 1, a cam-actuated timer switch 10 basically comprises a housing l2, a cam means 14 rotatably carried on a cam shaft 16 and having independent cam tracks 18, a switch means 20 responsive to cam means 14, a drive means 22 carried by housing means 12 and driving cam means 14, ramping means 21, a line switch means 23, and stop means 25.

Drive means 22 comprises a permanent-magnet synchronous gear motor 24. Motor 24 is suitably attached to housing means 12 by attachment means 26 which, in the illustrated embodiment, comprises screws 28 threaded into housing means 12. Gear motor 24 is coupled to cam means 14 through a gear train 30 which engages a gear 32 carried on the outer periphery of cam means 14. Switch means 20 comprises contact-carrying switch blades 34 affixed into slots 36 in housing means l2. Blades 34 are responsive to cam tracks 18.

Line switch means 23 switches power from a power supply (not shown) to motor 24 and includes an indexable switch blade 40, an actuator switch blade 42, and an index disc 44. A first electrical contact 46, staked to indexable switch blade 40, engages a second electrical contact 48 which is staked to actuator switch blade 42. A follower tip 50 disposed at a distal end of actuator switch blade 42 engages a cam track 18 of cam means 14. An index tip 52 disposed at a distal end of indexable switch blade 40 engages a face 54 of index disc 44.

Blades

40 and 42 are rigidly held in housing means l2. Another embodiment of line switch means 23 includes a double upper switch blade 56 shown in FlG. 8. Staked to double upper switch blade 56 is a third electrical contact 58. Third electrical contact 58 is in a position to interact electrically with first and second

electrical contacts

46 and 48. A tip 60 of double upper switch blade S6 engages stop ledge 62 on housing 12 to prevent it from following actuator switch blade 42 below a position predetermined by the distance between the stop ledge and cam means 14.

Cam-actuated timer switch includes a twoposition indexlocation means 68 to insure that cam shaft 16 resides in one of an indexed-in and an indexed-out" position in relation to housing 12. Means 68 comprises a pair of circumferential detent grooves 70 disposed on cam shaft 16 and a U-shaped index spring 72 carried by housing 12 and engaging the detent grooves. U-shaped index spring 72 is carried about and restrained by spring bosses 74 projecting from a top face 76 of housing 12.

Ramping means 21 axially indexes cam shaft 16 as the cam shaft rotates. Ramping means 21 includes a ramp-stop disc 78 rigidly affixed to cam shaft 16 having at least one first ramped projection 80 extending from a bottom face 82 of ramp-stop 78 and at least one cam lobe 84 extending from an outer periphery 86 of rampstop disc 78. Ramping means 21 further includes a spreader bar 88 having an aperture 90 passing therethrough, a second ramped projection 92, and an arcuate surface 94. Spreader bar 88 pilots in a spreader bar slot 96 in a frame member 66 and is pivotable about a distal end 98 of U-shaped index spring 72 which passes through aperture 90. First ramped projection 80 extending from ramp-stop disc 78 cam, upon rotation of cam shaft 16,-engages second ramped projection 92 on spreader bar 88. Additionally, arcuate surface 94 engages ends 98 and 99 of U-shaped spring 72. Frame member 66 is'secured to housing 12 by screws 100 passed through screw apertures 102 and threaded into holes 104 located in housing bosses 106 extending from rear face 76 of housing 12.

Stop means 25 provides a 'definite interference to manual turning of cam shaft 16 at preset points in a timing cycle. Two embodiments of stop means 25 are shown in FIGS. 2 and 3. FlG. 2 illustrates an overriding stop version 64 of stop means 25, and FIG. 3 shows a positive stop version 140 of stop means 25. Overriding stop version 64 includes an overriding stop member 112, a ramp-stop disc 78, a torsion spring 108, and retention means 110. Overriding stop member 112 includes a notched arm 114, an overriding stop projection 120, a first elongated aperture 116 and a second elongated aperture 118. Stop member 112 is pivotal about a first post 122 which extends from a top surface 124 through first elongated aperture 116. A second post 126 extending from top surface 124 of frame member 66 through second elongated aperture 118 limits the degree of pivoting of overriding stop member 112. Torsion spring 108 is carried about second post 126 with a first distal end 128 disposed in a notch 130 in notched arm 1l4and a second distal end 132 resting against first post 122 so as to produce a torque on over riding stop member 112 in a direction indicated by arrow 134. This torque forces stop projection 1,20 on stop member 112 against outer periphery 86 and cam lobes 84 of ramp-stop disc 78. Retention means 110, comprising an E-ring 111 in the illustrated embodi ment, fits in a groove 136 in second post 126 to retain overriding stop member 112 on the second post. A compression washer 113 is also added between member 112 and second post 126 to limit the wobble tendency of member 112.

A positive stop version 140 of stop means 25 is illustrated in FlG. 3. This version is similar to the overriding stop means version 64 except thatv overriding stop member l 12`is replaced by a positive stop member 142 and torsion spring 108 is eliminated. Positive stop apertures 144 disposed in member 142 are smaller than first and second

elongated apertures

116 and 118 in overriding stop member 112 so as to prevent a positive stop projection 146 on member 142 from overriding cam lobes 84 on ramp-stop disc 78.

In the` operation of cam-actuated timer switch 10, motor 24 drives gear 32 through-gear train 30 causing cam means 14 to rotate. Line switch means can -be best described by referring to diagrammatical.representations of switching within cam-actuated timer switch l0 as illustrated in FIGS. 4, 5, 6 and 7..A manual setting kob 147 is shown connected to cam shaft 16. An operator can grasp knob 147 in the arrangement of FlG. 4 and rotate cam shaft 16 to set timer switch 10. Upon reaching the desired setting, the operator then pulls the knob and the cam shaft means to an indexed-out position as shown in FlG. 5. Upon being indexed-out, index disc 44 moves out with cam shaft 16 and causes indexable switch blade 40 to return to a less-flexed position as shown in FIG. 5. Thereupon, first and second

electrical contacts

46 and 48 make contact and complete a circuit between a power source (not shown) and motor 24 causing timer switch 10 to start a timing cycle. At this point, follower tip 50 is resting on a neutral cam track 148 on cam means 14. During the timing cycle, switching means 20 responds according to a preselected program on independent cam tracks 18.

As the timing cycle progresses, and ramp-stop disc 78 rotates with cam means 14 and cam shaft 16, first ramped projection comes into engagement with sec'- ond ramped projection 92. ln FIG. 6, this engagement is just about to occur as shown in solid lines and has just occurred as shown in dotted lines. As cam shaft 16 rotates, projection 80 and projection 92 engages and causes spreader bar 88 to ramp in the direction of arrow 152 and ramp-stop disc 78 to move in the direction of arrow V138. As spreader bar 88 moves, arcuate surface 94 spreads-the ends 98 and 99 of U-shaped spring 72 to relieve tension against concentric detent grooves 70 so that cam shaft 16 can move easier in the direction of arrow 138. Follower tip S0 rests on a top cam track prior to and during the ramping action just described. Although cam shaft I6 is moved back into an indexed-in position, as shown by dotted lines in FIG. 6top cam track 150 prevents actuator switch blade 42 from dropping to open

electrical contacts

46 and 48. As the timing cycle progresses, follower tip 50 drops off top cam track 150 onto a neutral track 148, whereupon

contacts

46 and 48 reopen. This removes power from motor 24, and timer switch l0 is at rest and ready to be manually set again as shown in FIG. 7.

An additonal switching element in the form of double upper switch blade 56 is ilustrated in relation to actuator switch blade 50 and indexable switch blade 48 in FIG. 8. Downward movement of blade 56 may be prevented by a tip 60 of blade 56 engaging a stop ledge 62 carried by housing 12.

The overriding stop version 64 of stop means 25 provides a predetermined amount of torque resistance to manual turning of cam shaft 16. As shaft 16 is turned a cam lobe 84 on ramp-stop disc 78 engages overriding stop projection 120 on overriding stop member 112. To continue manual rotation of cam shaft 16, the force exerted by torsion spring 108 against stop member 112 must be overcome. This force may be adjusted by preselecting the strength of spring 108.-

The positive stop version 140 of stop means 25 provides at least one predetermined positive stop to manual turningv of cam shaft 16. As shaft 16 is turned a cam lobe 84 on ramp-stop disc 78 engages positive stop projection 146 on positive stop member 142. Cam shaft 16 must be indexed in to disengaged ramp-stop disc with positive stop member 142 before manual rotation of the cam shaft may be resumed.

What is claimed is:

l. In a cam-actuated timer switch having a housing, a cam means having a plurality of independent cam tracks, said cam means being rotatably carried on an axially-indexable cam shaft within said housing, a plurality of contact-carrying switch blades responsive to rotation of said cam means, and an electric motor, carried by said housing means, for driving said cam means, the improvement comprising:

a. a two-position index location means carried by said housing and engaging said cam shaft to provide said cam shaft with two axial index positions in spaced relation to said housing means;

b. ramping means, carried by said housing and coupled to said cam shaft, for moving said cam shaft axially from one of said index positions to the other of said index positions at predetermined angular positions during rotation of said cam shaft;

c. a stop means carried by said housing and coupled to said cam shaft for producing resistance to turning of said cam shaft at a preselected angular position; and

d. a line switch means for switching power to said electric motor in response to said axial movement of said cam shaft and to rotation of one of said independent cam tracks of said cam means.

2. The improvement to a cam-actuated timer switch as recited in claim 1 wherein said line switch means comprises:

a. an index disc connected to said cam shaft;

b. an indexable switch blade, including a first electrical contact, carried by said housing and engaging said index disc; and

c. an actuator switch blade carried by said housing means, including a second electrical Contact and a follower tip, wherein said second electrical contact engages said first electrical contact and said follower tip engages one of said cam tracks.

3. The improvement to a cam-actuated timer switch as recited in claim 2 further including a double-upper switch blade carried by said housing and having a third electrical contact interacting electrically with said first and second electrical contacts.

4. The improvement to a cam-actuated-timer switch as recited in claim 1 wherein said two-position index location means comprises a pair of circumferential detent grooves disposed on said cam Ashaft and a U-shaped index spring carried by said housing means and engaging said pair of circumferential detent grooves.

5. The improvement to a cam-actuated timer switch as recited in claim 1 wherein said ramping means includes:

a. a ramp-stop disc rigidly affixed to said cam shaft having at least one first ramped projection extending from a face of said ramp-stop disc and at least one cam lobe extending from an outer periphery of said ramp-stop disc; and

b. a spreader bar carried by said housing including a second ramped projection and an arcuate surface, said second ramped projection engaging said first ramped projection and said arcuate surface engaging said two-position index location means.

6. The improvement to a cam-actuated timer switch as recited in claim 1 wherein said stop means comprises a positive stop member rigidly connected to said housing and including a positive stop projection disengaging said cam lobe in one of said indexed positions of said cam shaft and engaging said cam lobe in the other position, whereby rotation of said cam shaft is prevented upon engagement of said cam lobe with said positive stop projection.

7. The improvement to a cam-actuated timer switch as recited in claim 1 wherein said stop means comprises:

a. an overriding stop member including an overriding stop projection extending therefrom and first and second elongated apertures disposed therein;

b. a first post extending from said housing means through said first elongated aperture about which said overriding stop member pivots;

c. a second post extending from said housing through said second elongated aperture to limit the degree of pivoting of said overriding stop member about said first post;

d. retention means for retaining said overriding stop member on said second post; and

e. a torsion spring carried by said second post and engaging said overriding stop member and urging it generally toward said cam shaft, whereby said overriding stop projection, upon rotation of said cam shaft, is engaged by said cam lobe on said ramp-stop disc, and rotation of said cam shaft is resisted by the force exerted by said spring against said overriding stop member so that additional torque must be applied to said cam shaft to urge said cam lobe to override said overriding stop projection and allow said shaft to continue to rotate.

* k k I

Claims

1. In a cam-actuated timer switch having a housing, a cam means having a plurality of independent cam tracks, said cam means being rotatably carried on an axially-indexable cam shaft within said housing, a plurality of contact-carrying switch blades responsive to rotation of said cam means, and an electric motor, carried by said housing means, for driving said cam means, the improvement comprising: a. a two-position index location means carried by said housing and engaging said cam shaft to provide said cam shaft with two axial index positions in spaced relation to said housing means; b. ramping means, carried by said housing and coupled to said cam shaft, for moving said cam shaft axially from one of said index positions to the other of said index positions at predetermined angular positions during rotation of said cam shaft; c. a stop means carried by said housing and coupled to said cam shaft for producing resistance to turning of said cam shaft at a preselected angular position; and d. a line switch means for switching power to said electric motor in response to said axial movement of said cam shaft and to rotation of one of said independent cam tracks of said cam means.

2. The improvement to a cam-actuated timer switch as recited in claim 1 wherein said line switch means comprises: a. an index disc connected to said cam shaft; b. an indexable switch blade, including a first electrical contact, carried by said housing and engaging said index disc; and c. an actuator switch blade carried by said housing means, including a second electrical contact and a follower tip, wherein said second electrical contact engages said first electrical contact and said follower tip engages one of said cam tracks.

4. The improvement to a cam-actuated timer switch as recited in claim 1 wherein said two-position index location means comprises a pair of circumferential detent grooves disposed on said cam shaft and a U-shaped index spring carried by said housing means and engaging said pair of circumferential detent grooves.

5. The improvement to a cam-actuated timer switch as recited in claim 1 wherein said ramping means includes: a. a ramp-stop disc rigidly affixed to said cam shaft having at least oNe first ramped projection extending from a face of said ramp-stop disc and at least one cam lobe extending from an outer periphery of said ramp-stop disc; and b. a spreader bar carried by said housing including a second ramped projection and an arcuate surface, said second ramped projection engaging said first ramped projection and said arcuate surface engaging said two-position index location means.

7. The improvement to a cam-actuated timer switch as recited in claim 1 wherein said stop means comprises: a. an overriding stop member including an overriding stop projection extending therefrom and first and second elongated apertures disposed therein; b. a first post extending from said housing means through said first elongated aperture about which said overriding stop member pivots; c. a second post extending from said housing through said second elongated aperture to limit the degree of pivoting of said overriding stop member about said first post; d. retention means for retaining said overriding stop member on said second post; and e. a torsion spring carried by said second post and engaging said overriding stop member and urging it generally toward said cam shaft, whereby said overriding stop projection, upon rotation of said cam shaft, is engaged by said cam lobe on said ramp-stop disc, and rotation of said cam shaft is resisted by the force exerted by said spring against said overriding stop member so that additional torque must be applied to said cam shaft to urge said cam lobe to override said overriding stop projection and allow said shaft to continue to rotate.