US3281547A

US3281547A - Range timer having parallel walls which include first and second magnetic portions

Info

Publication number: US3281547A
Application number: US320458A
Authority: US
Inventors: Joseph J Everard
Original assignee: AMF Inc
Current assignee: AMF Inc
Priority date: 1963-10-31
Filing date: 1963-10-31
Publication date: 1966-10-25
Anticipated expiration: 1983-10-25
Also published as: GB1061006A

Description

Oct. 25, 1956 J. J. EVERARD 3,281,547

RANGE TIMER HAVING PARALLEL WALLS WHICH INCLUDE FIRST AND SECOND MAGNETIC PORTIONS Filed Oct. 31, 1963 2 Sheets-Sheet l -59 FWJQ. R

j INVENTOR 25 T; I36 k Joseph J. Everard BY W ATTORNEY Oct. 25, I%@ J. J. EVERARD 3 281,547

9 RANGE TIMER HAVING PARALLEL WALLS WHICH INCLUDE FIRST AND SECOND MAGNETIC PORTIONS Filed Oct. 31, 1963 2 Sheets-Sheet 2 so a as 22 A 9 l IEIBHHHHH 8 8 97 I. i l 2 23- a9 1 F I396 4 i INVENTOR dosaph J. Everard W/aj/z ATTORNEY United States Patent Filed Oct. 31, 1963, Ser. No. 320,458 12 Claims. (Cl. 200-38) This invention relates to interval timers, and more particularly to electrical interval timers adapted to actuate a switch at the end of a preset, adjustable time interval.

Such timers normally contain a clock mechanism and an interval timing or interval measuring mechanism. The clock mechanism usually comprises a synchronous electric motor driving a reduction gear train. The interval measuring or interval timing device is driven by the gear train through a path of adjustable extent defining a timing interval, and is adapted to actuate a switch or sound an alarm or the like at the end of the interval.

Since these timers are usually to be built into an appliance, such as a kitchen range, which is to be controlled by them, their size is a major competitive factor. In particular, if the timer is enclosed within a box-like case or housing, it is highly desirable to have the dimension normally considered as the front-to-back dimension as small as possible. This permits the timer to take up as little space as possible behind a panel upon which it is normally mounted. Bulky components of inconvenient shape limit the freedom of the designer in arranging the timer components into a package of the desired shape and size.

The synchronous electric timing motor is usually the largest and most bulky of the individual timer components. It normally comprises a centrally located rotor surrounded by pole pieces, with the field coil either wound about the outside of the pole pieces, causing the motor to have a large diameter, or located as an axial extension on either end of the rotor, causing the motor to be relatively long axially.

It is an object of this invention to provide an electrical interval timer of the type described which is conveniently small in size, and in particular one in which the frontto-back dimension is relatively small, providing a thin timer which will require only a small depth behind a panel upon which it may be mounted.

It is another object of this invention to provide such an electrical interval timer in which the component parts of the synchronous timing motor may be mounted spaced apart from each other, permitting maximum design freedom to obtain an overall package of the desirable small size.

It is a still further object of this invention to provide such an electrical interval timer having relatively few components and being easy to assembly, thereby enabling it to be produced at relatively low cost.

The above objectives are achieved in this invention briefly and broadly by using the exterior walls of the timer case to provide magnetic coupling between the synchronous motor field coil and the stator and rotor assembly of the motor, thereby permitting the field coil and stator and rotor assembly to be located spaced apart from each other at any convenient position.

The manner in which the above and other objectives of this invention are achieved may be understood more clearly by reference to the following detailed description of a preferred embodiment of the invention, taken in conjunction with the drawings, which form a part of this specification, and in which:

FIG. 1 is a perspective view of the timer from the rear and above, with the rear wall shown dashed to permit viewing of the timer components;

FIG. 2 is a rear elevation of the timer with the rear wall being removed and a portion being shown in section;

FIG. 3 is a top plan view of the timer with one of the spacers and a portion of the front wall being cut away;

FIG. 4- is a section taken along line 4-4 of FIG. 2;

FIG. 5 is a side elevation as viewed from the left in FIGS. 1 and 2, with one of the spacers being cut away;

FIG. 6 is a detail view from above, partially in section and partially in full, of the timing motor rotor, a portion of the stator, and the mounting of these elements to the front wall;

FIG. 7 is a view, partially in section and partially in full, of the motor field coil, taken along line 7-7 of FIG. 2;

FIG. 8 is a fragmentary section taken along line 8-8 of FIG. 3, showing the antireverse mechanism;

FIG. 9 is a fragmentary section of the one-way clutch mechanism taken along line 9-9 of FIG. 2; and

FIGS. 10 and 11 are fragmentary elevations, with a portion in section, showing the operation of the timing cam in actuating the leaf Spring switch, with FIG. 10 showing the relative positions of the timing cam and switch at the beginning of a timing interval, and with FIG. 11 showing the leaf spring switch actuated by the timing cam at the end of a timing interval.

Referring now to FIG. 1, all of the timer components are mounted upon, and located substantially within, a case comprising rectangular front and

rear walls

20 and 21, respectively, of magnetic material, that are held in spaced, parallel relationship by means of

cylindrical spacers

22, 23 and 24 and a rigid, substantially rectangular terminal strip of insulating material 25.

The timer is driven by a synchronous electric motor comprising a stator and rotor assembly 26, a field coil 27, and front and

rear walls

20 and 21 which serve to magnetically couple the field coil to the stator and rotor assembly.

Walls

20 and 21, therefore, serve both as a structural support and as an operating portion of the timing motor. Stator and rotor assembly 26 is located at the lower left of FIG. 1, and field coil 27 at the lower center of that figure.

A reduction gear train 28 occupies the upper left-hand portion of FIG. 1, a timing cam 29 is adjacent to gear train 28 and to its right, and a leaf spring switch 30 (which may be seen more clearly in FIG. 2) is located just to the right of timing cam 29.

In the operation of the timer, the synchronous motor drives reduction gear train 28, with the combination of motor and gear train comprising a clock mechanism. Timing cam 29 is driven by the clock mechanism angularly about its axis from an adjustable, preset initial angular position to a fixed final angular position, with the angular path between these two positions defining the adjustable timing interval. When timing cam 29 reaches the final angular position defining the end of the timing interval, it actuates leaf spring switch 30, which in turn controls one or more external circuits which may be connected to the timer.

Synchronous electric timing motor Details of stator and rotor assembly 26 of the timing motor may be seen in FIGS. 1, 2, 5 and 6. Stator and rotor assembly 26 is of generally cylindrical configuration, being mounted between, and having its axis perpendicular to,

walls

20 and 21. It comprises two fixed

pole pieces

32 and 33 of magnetic material and a cupshaped rotor 34 mounted for rotary motion within the pole pieces.

Pole pieces 32 comprises a flat, annular base portion 35 from whose circular periphery equally spaced pole fingers 36 project axially. Base 35 is placed flat against the outer surface of rear wall 21, and pole fingers 36 project through suitable openings in the wall into the case. An annular flange 37, coaxial with pole pieces 32, projects from rear wall 21 through the inner opening 38 in base 35, extending slightly outwardly of the outer surface of base 35. Flange 37 serves to position base 35 upon wall 21, and pole piece 32 is secured to wall 21 by staking flange 37 to base 35.

Pole piece 33 comprises a flat annular base portion 41 from whose periphery pole fingers 42 project axially. Pole fingers 42 are equal in number to the pole fingers 36 of pole piece 32, and like pole fingers 36, form an equally spaced annular series. As may be seen in FIGS. and 6, pole piece 33 is mounted upon a housing 43 of magnetic material, which housing is in turn mounted upon front wall 20. One end 44 of housing 43 is generally semi-circular in cross section and projects to the left, toward front wall 20, from a radially extending annular flange 45. The other end of housing 43 comprises a cylindrical core 46, of slightly smaller diameter than end 44, which is coaxial with and projects inwardly fpom flange 45. The inner end of core 46 extends into the cavity of cup-shaped rotor 34.

The end of semi-circular portion 44 of housing 43 fits closely within a semi-circular slot 47 in front wall and is attached rigidly to the front Wall. The attachment may be conveniently made, as it is in this preferred embodiment, by having the end surface 48 of semi-circular portion 44 project outwardly slightly beyond the outer surface 49 of front wall 20, and by staking end surface 48 to outer surface 49 of wall 20. The considerable area of semi-circular portion 44 which is in contact with the corresponding semi-circular slot 47 in front wall 20 permits a sufficiently rigid attachment of housing 43 to the wall to provide the sole mounting for housing 43 and for pole piece 33 .and rotor 34 which are mounted thereon.

Rotor 34 is mounted upon a shaft 52 by being pressed upon the serrated end 53 thereof. A fiber washer 54 mounted upon shaft 52 spaces rotor 34 from the inner end of core 46. Shaft 52 passes axially through, and is suitably journaled within, core 46. Motor pinion 51 is fixedly attached to the outer end of shaft '52 and is partially enclosed by semi-circular portion 44 of housing 43. The outer tip of shaft 52 which projects beyond pinion 51 is loosely received within an aligned circular opening 55 in front wall 26. While in the preferred embodiment shaft 52 is solely supported by and journaled Within core 46 of housing 43, it is alternatively possible to provide additional support for shaft 52 should it be needed by journaling the outer end in opening 55.

The mounting of

pole pieces

32 and 33 is such that the circular series of

pole fingers

36 and 42 are coaxial with rotor 34- and shaft 52, with their common axis being perpendicular to the front and rear walls. Each pole finger projects slightly into the space between adjacent pole fingers of the oppositely disposed pole piece and is spaced substantially at an equal angular distance from the two pole fingers between which it projects.

Field coil 27, as may be seen in FIGS. 1 and 2, is mounted upon an axis parallel to, but spaced from, the axis of stator and rotor assembly 26. Details of field coil 27 and its mounting may be seen in FIG. 7. Field coil 27 includes a winding 57 which is arranged as a hollow cylinder and is completely encapsulated in any suitable solid electrical insulating material, such as the usual polymeric synthetic resinous materials, the insulating material forming a cylindrical body 58 having an axial cylindrical bore 59 and a projecting boss 60, the latter accommodating leads 61 and 62 for winding 57.

Field coil 27 is mounted upon a core 63 of magnetic material, the ends of core 63 being mounted upon front and

rear walls

20 and 21, respectively. Core 63 comprises a main cylindrical portion 64 having at one end a radially extending flange 65 with inner and outer

radial shoulders

66 and 67, respectively. A short cylindrical portion 68 of reduced diameter projects axially from flange 65, and a similar short cylindrical portion of reduced diameter 69 projects axially from the other end of main cylindrical portion 64. Short cylindrical projection 68 is received within a suitable circular opening 71 in front Wall 20, and core 63 is rigidly attached to front wall 20 as by staking the outer surface of projection 68 to the outer surface of the wall.

Bore 59 of body 58 slidably embraces the main cylindrical portion 64 of core 63, and body 58 is placed upon main portion 64 so as to abut inner shoulder 66 of flange 65. Field coil 27 is fixed axially upon core 63 by means of a spring metal washer 72 whose inner edges grip the surface of main cylindrical portion 64 and whose periphery exerts an axial bias upon field coil 27, pressing it tightly against shoulder 66. Short cylindrical projection 69 is received slidably within a suitable circular opening 73 in rear Wall 21, to which it is detachably fixed, as by a screw 74 cooperating with a threaded axial recess extending inwardly from the end of projection 69.

When winding 57 of field coil 27 is energized by suitable A.C. power 'via leads 61 and 62, an alternating magnetic field is created in the vicinity of the field coil. This alternating magnetic field is coupled, via magnetic core 63, to front wall 20 and rear wall 21. Magnetic flux is coupled, via magnetic front wall 20 and magnetic housing 43 rigidly attached thereto, to pole piece 33 which is rigidly fixed to housing 43. Magnetic rear wall 21 couples the magnetic flux to pole pieces 32 which is rigidly attached to it. A rotating magnetic field is thus supplied to

pole pieces

32 and 33.

Rotor 34, which may advantageously be molded from a synthetic resinous ferromagnetic composition or a ceramic ferromagnetic material, is permanently magnetized in any pattern which adapts it to be driven by such a rotating magnetic field. It may thus be magnetized so as to have a plurality of peripheral areas spaced equally about the rotor and magnetized axially of the rotor. For a detailed description of the operation of motors having similar rotor and pole piece configurations, reference may be had to US. Patents 2,981,855 to Van Lieshout et al. and 3,014,141 to Riggs.

Rectangular notches 75 in the ends of each of

pole fingers

36 and 42 open in the same angular direction and provide sufficient unbalance of the magnetic field to insure certain starting of the motor. They thus prevent rotor 34 from stopping on a dead center spot in which all the magnetic forces are equally balanced.

Walls and 21 of magnetic material serve a structural function, in mounting and containing the various other timer components, and also function as a working portion of the electromagnetic timing motor. The use of the walls as a magnetic coupling between the field coil and the pole pieces permits the field coil and the stator and rotor assembly to be spaced substantially and to be located anywhere within the case. Their positions may be determined solely by the factor of convenience of parts placement, and the designer is thus permitted a wide range of freedom in arranging the component parts of the timer so as to create the thinnest and most-compact timer package possible.

While the field coil mounting arrangement shown and described is preferred, it is not at all necessary that the field coil be mounted upon a cylindrical core perpendicular to

walls

20 and 21; it may be mounted by any other desired means, including brackets, with its axis in any direction, the only requirement being that the alternating magnetic field created by the field coil be coupled to walls 20 and 2.1, and thereby to the pole pieces.

Reduction gear train Reduction gear train 28, connecting timing motor pin- 1011 5.1 to timing cam 29, comprises generally a group of large gears and pinion gears mounted for rotation about four axes parallel to each other and perpendicular to

walls

20 and 21, and includes an anti-reverse mechanism and a one-way clutch mechanism.

Gear 80 meshes with timing motor pinion 51 and is rigidly attached to pinion 81. The combination of gear 80 and pinion 8 1 is loosely journaled for rotation upon a shaft 82 which is rig-idly mounted in front wall 20, and is relative-1y short, extending inwardly from front wall 20 only a short distance beyond the inner surface of gear 80. Gear 83 meshes with pinion 81 and is rigidly attached to pinion 84. Both gear 83 and pinion 84 are loosely journaled for notation upon a shaft 85 which is perpendicular to front and

rear walls

20 and 21 with each of its ends being mounted within suit-able openings in a separate one of the walls.

Gear 86 meshes with pin-ion 84 and is rigidly attached to pinion '87, with the combination of gear 86 and pinion 87 being loosely journaled for rotation upon a shaft 88 which has an end mounted in a suitable opening in each of walls 20 and .21 and extends in a direction parallel to shaft 85. Gear 8 9 meshes with pinion 87 and is rigidly attached to pinion 90, with the combination of gear 89 and pinion 90 being loosely journaled for rotation upon shaft 85. From pinion 90, motion is transmitted via gear 91 and pinion 92, rigidly connected and loosely journaled for rotation upon shaft 88, to gear 93 which meshes with pinion 92. Pinion 94 is rigidly attached to gear 93, and the combination is loosely journaled for rotation upon shaft 85. Gear 95 meshes with pinion 94 and, through a one-way clutch mechanism, drives coaxial pinion 96 which meshes with the peripheral set of gear teeth 97 which are integral with timing cam 29.

The one-way clutch mechanism may be viewed from above in FIG. 3 and may be seen in section in FIG. 9. A coaxial cylindrical projection 100 from one end of pinion 96 is loosely journaled in an appropriate opening in front wall 20. A somewhat similar short cylindrical projection 101 extends from the other end of pinion 96 and is coaxial therewith. A cylindrical shaft .102 of reduced diameter extends coaxially from the end of pin-ion projection .101. Gear 95 is loosely journaled for rotation upon shaft 102 and bears an integral, hollow cylindrical projection 103 extending toward pinion 96. The outer diameter of cylindrical projection 103 is equal to the outer diameter of pinion projection 1, and the ends of the two projections are adjacent.

A wire coil spring 104 is mounted upon, and is in frictional engagement with, the outer surfaces of projections 101 and 103. A spring washer 105 or the like mounted upon shaft .102 engages the outer surface of gear 95 and retains it axially upon shaft 102. The end .106 of shaft 102 is loosely journaled for rotation within a suitable opening in front wall 20.

The operation of the one-way clutch mechanism depends upon the frictional engagement of coil spring 104 with the outer surfaces of projections .10 1 and 103, and the degree of this frictional engagement depends upon the direction in which pin-ion 96 and gear 95 are rotated relative to each other. When gear train 28 is driven by motor pinion '51, gear 95 will rotate in a clockwise direction, as viewed fro-m rear wall 21. This results in projection 103, which is rig-idly attached to gear 95, attempting to rotate in a clockwise direction with respect to projection 101 and shaft 102 upon which it is loosely journaled. Wire coil spring 104 is so wound, as may be seen in FIG. 3, that when projection 103 tends to turn in a clockwise direction with respect to projection .101, the frictional engagement of the surfaces of each of these two projections with the spring tends to wind the spring more tightly, constricting the inner diameter of its turns, and causing it to grab the surface of both projections.

This results in pinion 96 being driven by gear 95 so that the cam, by virtue of the engagement of its peripheral gear teeth 97 with pinion 96, will normally be driven in a clockwise direction as viewed from front wall 20.

If the timing motor is not driving gear train 28, and timing cam 29 is rotated in a clockwise direction as viewed from front wall 20, then the one-way clutch mechanism operates to disconnect timing cam 29 and pinion 96 from the remainder of :gear train 28. This clutch disengagement results from the fact that a clockwise rotation of timing cam 29 (viewed from front wall 20) results in a counter-clockwise motion of pinion 96, when viewed from the same aspect. Since gear is at rest, this motion of pinion 96 results in projection 101 attempting to turn in a counterclockwise direct-ion with respect to projection 102 attached to gear 95. This relative motion is transmitted to spring 104 via its frictional engagement with the surfaces of these two projections, and it tends to unwind or loosen coil 104, thus decreasing its frictional engagement with the surfaces of these two projections. This decreased frictional engagement removes the driving connection between pinion 96 and gear 95, and thus permits timing cam 29 to rotate in a clockwise direction and pinion 96 to be rotated thereby in a counterclockwise direction, while disengaged from gear 95 and the remainder of reduction gear train 28. As will be described below, this disengaging feature permits manual adjustment of timing cam 29. The one-Way clutch mechanism is thus engaged by clockwise motion of projections 101 and 103 with respect to each other and disengaged by counterclockwise motion.

A synchronous motor of the type described herein is capable, when first started, of rotation in either direction. Therefore, an anti-reverse mechanism is included in gear train 28 to permit rotation of the motor and gear train in only the desired direction. The anti-reverse mechanism used may be seen in FIG. 8 and comprises basically a ratchet wheel acting in cooperation with an antireverse arm 111. Ratchet wheel 110 is fixedly attached to the innermost side of gear 80 and bears a plurality of ratchet teeth, each tooth having a smooth cam surface of gradually increasing radius moving in the counterclockwise direction as viewed in FIG. 8, and ending sharply in an inwardly extending radial surface. Anti-reverse arm 111 is mounted for pivotal motion about shaft 88, and bears two curved arms 112 and 113 each having an inwardly turned end adjacent to ratchet wheel 110. The ends of arms 112 and 113 are adapted to ride upon the cam surfaces of the teeth of ratchet wheel 110 as long as gear 80 is rotating in a clockwise direction as viewed in FIG. 8. Whenever gear 80 commences to rotate in a counterclockwise direction, the inwardly turned end of either arm 112 or 113 engages the outwardly extending radial surface of one of the ratchet teeth on wheel 110, stopping gear train motion in that improper direction and causing the motor to commence to rotate in the desired direction.

Interval timing mechanism The interval timing mechanism comprises manually adjustable interval timing cam 29 which is driven by the clock mechanism, and spring leaf switch 30 which is actuated by timing cam 29 at the end of the preselected timing interval to control one or more external circuits.

Interval timing cam 29 is a generally cylindrical structure of electrical insulating material mounted for rotation about an axis perpendicular to front and

rear walls

20 and 21, respectively. The cam structure may be conveniently hollow, having a roughly cylindrical cam surface 115 of substantial width supported by radial webs 116 upon an axial core 117 (FIG. 1). A short cylindrical projection 118 extends axially from core 117 and is loosely journaled for rotation in an appropriate opening in rear wall 21. An integral frusto-conical knob 119 extends from the other end of cam 29 and is loosely journa-led adjacent to its connection to the main body of cam 29 in a suitable opening 120 in front wall 20, as may be seen in FIG. 3, where a portion of front wall 20 is cut away to afford a view of the mounting of knob 119 therein. Knob 119 projects outwardly a substantial distance from the surface of front wall 20, and provides the manual means for adjustment of the angular position of cam 29. The circular series of gear teeth 97 are mounted upon the main body of the cam adjacent to front wall 20. As may be seen from the end views in FIGS. 2, l and 11, cam surface 115 is of a constant radius for approximately 180, and then gradually diminishes in radius moving in a counterclockwise direction as viewed in the figures, with the portions of minimum and maximum radius being connected by a radial shoulder 121.

Spring leaf switch 30 comprises three generally parallel vertically extending spring leaf arms: left-hand member 122, center member 123, and right-hand member 124, with the designations of these members corresponding to their positions as viewed in the figures. The upper ends of vertically extending

spring leaf arms

122, 123 and 124 are located adjacent to cam surface 115, and either arm 122 or both

arms

122 and 123 will be in contact with cam surface 115, depending upon the angular position of cam 29. The end of center spring leaf arm 123 extends upwardly for a slight distance beyond the end of left-hand spring arm 122. Leftand right-hand

spring leaf arms

122 and 124 each carries a single inwardly facing

contact button

125 and 126, respectively, located in opposed operative relation with respect to contact

buttons

127 and 128 mounted upon center spring leaf 123 and extending to the left and right, respectively.

A spacing member 130 of insulating material is mounted upon the spring leaf arms toward their upper ends, and comprises a generally rectangular main body 131 which loosely extends through a suitable opening in central spring leaf arm 123 and has left-hand and right-hand horizontally projecting

ears

132 and 133, respectively, which loosely extend through suitable openings in left-hand spring leaf arm 122 and right-hand spring leaf arm 124, respectively. The openings in the leftand right-hand spring leaf arms, while sufficiently large to admit

ears

132 and 133, are not large enough to admit main body portion 131, which thus serves to maintain a minimum spacing between the leftand right-hand spring leaf arms.

The lower ends of

spring leaf arms

122, 123 and 124 are connected to

terminals

134, 135 and 136, respectively. Each of these terminals is attached to its corresponding spring leaf arm and to the horizontally extending portion 137 of terminal strip 25 by means of a rivet or the like. Each terminal extends through a suitable opening in horizontal portion 137 and projects downwardly a substantial distance below the bottom surface thereof, to provide electrical connections for external circuits. Wire 62 from one end of field coil winding 57 is connected to terminal 135. Wire 61 from the other end of winding 57 is connected to terminal 138, which is similar in structure and mounting to the other terminals, but spaced therefrom.

Terminal strip 25 comprises a rectangular horizontally extending portion 137 bordered by a vertically extending edge 139 which projects above and below horizontal portion 137. Short projections of rectangular cross section 140 extend outwardly from edge 139 and are received within appropriate slots in both front and

rear walls

20 and 21, whereby terminal strip 25 is mounted upon those two walls and serves also as a spacing means. Only those projections 140 from edge 139 which cooperate with rear wall 21 are shown in FIG. 1; projections 140 on the other side of terminal strip 25 are identical.

The manner of mounting the various components in this timer permits easy and rapid assembly.

Shafts

85, 88 and 106, mounting components of gear train 28, are slidably received within suitable openings in rear wall 21, as is extension 118 of axial core 117 of the timing cam 29.

Spacers

22, 23 and 24, and core 64 of field coil 27, all have extensions which fit slidably within suitable openings in rear wall 21, and the rear wall is then attached to these members by means of screws passing through openings in the rear wall and engaging threaded bores in the members. The projections 140 of terminal strip 25 likewise are received slidably within suitable openings in wall 21. The only timer component which is rigidly and nonremovably attached to the rear wall is pole piece 32, and this is connected only to the rear wall and not to any other timer components. Therefore, in assembling the timer, all of the components may be assembled and mounted upon front wall 20, pole piece 35 may be fixed upon rear wall 21, and rear wall 21 may then be slidably placed upon those members which are journaled in it, and the appropriate screws inserted and tightened to complete the assembly.

Detailed timer operation When the timer is in operation, the clock mechanism, comprising the synchronous timing motor and the reduction gear train, rotates timing cam 29 at a constant angular rate, and the extent of the adjustable timing interval is defined by the amount of time required to rotate timing cam 29 from an adjustably preset initial angular position to the final angular position shown in FIG. 11.

The initial position of timing cam 29 is manually present by rotating knob 119 in such a direction as to turn timing cam 29 counterclockwise, as viewed in FIGS. 2, 10 and 11. As described above, the timing cam, when rotated in this direction, is disconnected by means of the one-way clutch mechanism from most of the reduction gear train and the timing motor, thereby permitting easy adjustment of its initial position. The farther this initial angular position is from the fixed final position shown in FIG. 11, the longer the timing interval. Knob 119 will normally cooperate with some fixed indicia, not shown, to relate the cams angular position to time and indicate to the user the extent of the timing interval.

In FIG. 10, timing cam 29 is shown rotated to its maxi- :mum counterclockwise position, defining a maxi-mum timing interval. Left-hand spring member 122 is so positioned with respect to cam surface that even in its maximum counterclockwise position, with the portion of cam surface 115 of minimum radius contacting the end of left-hand spring arm 122, arm 122 is flexed to the right sufficiently far for contact button 125 on left-hand arm 122 to be in contact with contact button 127 attached to center spring arm 123. The main portion 131 of insulated spacer 130 maintains sufficient spacing between left-hand spring arm 122 and right-hand spring arm 130 so that, when the left-hand spring arm is making contact with center spring arm 123, right-hand spring arm 124 is always maintained out of contact with the center spring arm.

Once the timing cam has been initially positioned to preset the timing interval, alternating current power is applied to field coil 27 via terminals and 138. The synchronous timing motor commences to run and reduction gear train 28 drives timing cam 29 in a counterclockwise direction. As timing cam 29 rotates, the increasing radius of cam surface 115 flexes left-hand spring arm 122 and center spring arm 123 further to the right. Even though center spring arm 123 is flexed toward the right, it will not make contact with right-hand spring arm 124, since the main portion 131 of insulated spacer 130 is also pushed to the right by means of left-hand spring arm 122 and maintains right-hand spring arm 124 out of contact with the center spring arm. In FIG. 2, timing cam 29 is shown just before the end of a timing cyc e.

The end of the timing cycle occurs when shoulder 121 of timing cam 29 clears the top of the left-hand spring arm 122. The result, as shown in FIG. 11, is that lefthand spring arm 122 snaps to the left under its own resilience and abuts that portion of cam surface 115 of minimum diameter, while the longer end of center spring member 123 is engaged by the portion of cam surface 115 of maximum diameter, resulting in the disengagement of

contact buttons

125 and 127 and in the opening of any electrical circuit connected between

terminals

134 and 135. At the same time, since left-hand spring arm 122 has moved to the left and away from central spring arm 123, right-hand spring arm 124 is no longer blocked by insulated spacer 130 from contact with the central spring arm and moves to the left by virtue of its natural resilience so that contact button 126 mounted thereon engages contact button 128 of central spring arm 123, thus making electrical contact between

terminals

135 and 136.

The use of a double-throw switch provides versatility and permits the timer, at the end of a timing cycle, to open a normally closed circuit connected between

terminals

134 and 135, or to close a normally open circuit connected between

terminals

135 and 136. After the end of a timing cycle, the synchronous timing motor may be turned off by opening the circuit to field coil 27, or this may be performed automatically by switch 30 by means of suitable external connection.

While a preferred embodiment of this timer has been described in detail, it is obvious that many variations and modifications which may suggest themselves to those skilled in the art may be made Without departing from the scope of the invention, which is defined solely in the claims.

What is claimed is:

1. An interval timer comprising the combination of:

a case having a pair of parallel external walls which include first and second magnetic portions;

a gear train;

interval timing means connected to said gear train to be driven thereby through a path of preset extent, defining a timing interval, to a switch actuating position;

a magnetic rotor rotatably mounted on a first axis and connected to said gear train for driving said train by rotating;

two pole pieces disposed adjacent to said rotor,

each said pole piece being connected by magnetic material to a separate one of said magnetic portions of said case;

a motor field coil disposed about a second axis displaced from said first axis,

said first and second magnetic portions of said case being connected by magnetic material to first and second spaced points, respectively, immediately adjacent and magnetically coupled to opposite ends of said field coil so that when said field coil is energized by AC. power the alternating magnetic field created thereby is coupled by said magnetic portions of said case to said pole pieces so as to rotate said rotor; said gear train, said interval timing means, said rotor, said pole pieces, and said field coil all being mounted upon and substantially within said case and between said Walls,

whereby said case serves to mount and enclose the component parts of the timer and also functions as a portion of the electromagnetic motor.

2. An interval timer in accordance with claim 1 and said magnetic material comprising a magnetic core upon which said field coil is disposed,

each end of said core being directly fastened to a separate one of said magnetic portions of said case.

3. An interval timer in accordance with claim 2 and wherein:

each of said pole pieces comprises a flat base portion and a circular spaced series of generally rectangular pole fingers projecting perpendicularly from said base portion,

said pole pieces being disposed with said base portions parallel and said two series of pole fingers coaxial with said first axis and projecting toward each other, with the pole fingers of one of said pole pieces directed toward the spaces between the pole fingers of the other of said pole pieces; said rotor is operatively disposed within said circular series of pole pieces; and each said fiat base portion is rigidly mounted upon and magnetically connected with a separate one of said magnetic portions of said external walls of said case. 4. A timer comprising in combination: two spaced parallel walls,

at least one of said walls having a portion of magnetic material; a timing mechanism mounted upon and substantially between said walls; a field coil mounted upon and between said walls; an armature mounted upon and between said walls in a position spaced substantially from said field coil, and adapted to be actuated by a magnetic field in its immediate vicinity so as to provide mechanical power for said timing mechanism; first magnetic means disposed between said walls and connecting a point immediately adjacent said field coil with a first point on said Wall portion of mag netic material; second magnetic means disposed between said walls and connecting a point in the immediate vicinity of said armature with a second point on said wall portion of magnetic material spaced from said first point; whereby, when said filed coil is energized, the magnetic field thereby created is coupled via said first and second magnetic means and said wall portion of magnetic material to the immediate vicinity of said armature, thereby actuating said armature. 5. A timer comprising in combination: two spaced parallel walls,

each of said walls having a portion of magnetic material; a timing mechanism mounted upon and substantially between said walls; a magnetic core mounted upon and between said walls with its axis perpendicular to said walls,

each end of said magnetic core being magnetically connected to said portion of magnetic material of a separate one of said walls; a field coil mounted upon and coaxial with said core to provide a solenoid; an armature mounted upon and between said walls and being spaced substantially from said solenoid, and adapted to be actuated by a magnetic field in its immediate vicinity so as to provide mechanical power for said timing mechanism; magnetic means connecting each of two spaced points immediately adjacent said armature to said portion of magnetic material of a separate one of said walls, each point of connection of said magnetic means to said portion of magnetic material being spaced a substantial distance from the point of connection of the corresponding end of said magnetic core to said portion of magnetic material; whereby, when said field coil is energized, the magnetic field thereby created is coupled via said core, said portions of magnetic material of said walls, and said magnetic means, to the immediate vicinity of said armature and thereby actuates said armature. 6. An interval timer comprising in combination: two spaced parallel Walls,

each of said walls having a portion of magnetic material; a gear train;

a magnetic rotor rotatably mounted on a first axis and operatively connected to said gear train for driving said train by rotating;

two pole pieces disposed adjacent to said rotor,

each said pole piece being connected by magnetic material to said mag-netic portion of a separate one of said Walls;

a field coil disposed about a second axis displaced from said first axis,

each said wall portion of magnetic material being connected by magnetic material to a separate one of two spaced points immediately adjacent and magnetically coupled to opposite ends of said field coil so that when said field coil is energized with AC. power the alternating magnetic field thereby created is coupled by said wall portions of magnetic material to said pole pieces so as to rotate said rotor;

said gear train, said interval timing means, said rotor, said pole pieces, and said field coil all being mounted upon and substantially between said walls,

whereby said walls serve to mount and contain the component parts of the timer and also function as a portion of the electromagnetic mot-or.

7. An interval timer comprising in combination:

two spaced parallel walls,

each of said walls having a portion of magnetic material;

a gear train;

a magnetic rotor connected to said gear train and rotatably mounted on an axis perpendicular to said walls for driving said gear train by rotation;

two pole pieces disposed adjacent to said rotor,

each said pole piece being connected by magnetic material to said magnetic portion of a separate one of said walls;

a magnetic core disposed between said walls, parallel to and displaced laterally from said axis of rotation of said rotor,

each end of said core being connected to said portion of magnetic material of a separate one of said walls;

a field coil disposed upon said magnetic core;

said gear train, said interval timing means, said rotor,

and said pole pieces being mounted upon and substantially between said walls;

whereby, when said field coil is energized with AC. power the alternating magnetic field thereby created is coupled by said core and said wall portions of magnetic material to said pole pieces so as to rotate said rotor, said walls thereby serving .to mount and contain the component parts of the timer therebetween and also functioning as a portion of the electromagnetic motor.

8. An interval timer comprising in combination:

two spaced walls,

each of said walls having a magnetic material portion;

a gear train;

a switch;

an interval timing means,

having a cam with gear means connected to said gear train so that said gear train is adapted to rotatably drive said cam in one angular direction, and having means to manually adjust the angular position of said cam,

said cam having cam surface means to actuate 12 said switch when said cam occupies a predetermined angular position corresponding to the end of a timing cycle;

two pole pieces disposed adjacent to said rotor,

each said pole piece being connected by magnetic material to said magnetic material portion of a separate one of said walls; a field coil disposed about a second axis displaced from said first axis,

said magnetic material portion of each of said walls being connected by magnetic material to a separate one of two spaced points immediately adjacent and magnetically coupled to opposite ends of said field coil, so that when said field coil is energized by A.C. power the alternating magnetic field created thereby is coupled by said magnetic material wall portions to said pole pieces so as to rotate said rotor;

one-way clutch means provided in said gear train close to said cam so that said gear train can rotatably drive said cam in said one angular direction, and

said cam, when rotated by said manual adjusting means in said one angular direction, is drivingly disconnected from said rot-or and most of said gear train so as to permit manual adjustment of the initial angular position of said cam while the rotor remains stationary;

said gear train, said switch, said cam, said rot-or, said pole pieces, said field coil and said clutch means being mounted upon and substantially between said walls,

whereby said walls serve to mount and contain the components of the timer therebetween and also function as a portion of the electromagnetic motor.

9. An interval timer in accordance with claim 8 and wherein:

said walls are parallel; said interval timing cam is rotatably mounted on an axis perpendicular to said walls,

said cam having two oppositely extending axial projections each of which is journaled in a corresponding bearing opening in a separate one of said walls, and one of said axial projections being of substantial diameter and projecting a substantial distance beyond the wall in which it is journaled in a direction away from said cam, whereby it is adapted to serve as a manual adjusting knob for said cam. 10. An interval timer in accordance with claim 8 and wherein:

said walls are parallel; and said first and second axes are parallel to each other and perpendicular to said walls; and having in addition: said magnetic material including a magnetic core disposed along said second axis,

said field coil being mounted upon said core, and each end of said core being directly connected to and rigidly mounted upon said magnetic material portion of a separate one of said walls. 11. An interval timer in accordance with claim 10 and wherein:

said interval timing cam is rotatably mounted on an axis perpendicular to said walls,

said-cam having two oppositely extending axial projections each of which is journaled in a corresponding bearing opening in a separate one of said walls, and one of said axial projections being of substantial wherein said walls are parallel, each said wall having at least one straight edge which is parallel to a corresponding straight edge of said other wall; and said cam surface means of said interval timing cam is of electrically insulating material; and further comprising: a terminal strip of rigid electrically insulating material having two parallel sides and a top and bottom,

said strip being mounted upon and between said walls adjacent said straight edges thereof, with each said side being connected to a separate one of said walls, said top of said strip facing toward the space between said Walls and said bottom facing away from said walls; and a plurality of electrical terminals mounted upon said terminal strip and projecting downwardly from the bottom thereof; and said switch comprises a plurality of metallic spring fingers,

each said finger being connected to a separate one of said terminals and projecting upwardly therefrom and adjacent said cam surface means, and

at least one of said fingers being disposed to be contacted by said cam surface means in such a manner that said switch is actuated by said cam surface means when said cam reaches said predetermined angular position defining the end of a timing cycle.

References Cited by the Examiner UNITED STATES PATENTS 2,448,196 8/1948 Shee.

2,541,830 2/1951 Phaneuf 310-163 X 2,670,039 2/1954 Berkholde-r 20048 X 2,700,077 1/1955 Morrison 200 3s 2,979,580 4/1961 Tinn et al ZOO-38 3,027,469 3/1962 Sidell 310 41 3,164,734 1/1965 Heinzen 310-254 x BERNARD A. GILHEANY, Primary Examiner.

25 H. M. FLECK, Assistant Examiner.

Disclaimer 3,281,547.Joseph J. Everard, Manitowoc, Wis. RANGE TIMER HAVING PARALLEL WALLS WHICH INCLUDE FIRST AND SEC- OND MAGNETIC PORTIONS. Patent dated Oct. 25, 1966. Disclaimer filed May 26, 1972, by the assignee, AMF Incorporated. Hereby enters this disclaimer to claims 1 to 7 of said patent.

[Ofiicial Gazette August 15, 1.97%.]

Claims

1. AN INTERVAL TIMER COMPRISING THE COMBINATION OF: A CASE HAVING A PAIR OF PARALLEL EXTERNAL WALLS WHICH INCLUDE FIRST AND SECOND MAGNETIC PORTIONS; A GEAR TRAIN; INTERVAL TIMING MEANS CONNECTED TO SAID GEAR TRAIN TO BE DRIVEN THEREBY THROUGH A PATH OF PRESET EXTENT, DEFINING A TIMING INTERVAL, TO A SWITCH ACTUATING POSITION; A MAGNETIC ROTOR ROTATABLY MOUNTED ON A FIRST AXIS AND CONNECTED TO SAID GEAR TRAIN FOR DRIVING SAID TRAIN BY ROTATING; TWO POLE PIECES DISPOSED ADJACENT TO SAID ROTOR, EACH SAID POLE PIECE BEING CONNECTED BY MAGNETIC MATERIAL TO A SEPARATE ONE OF SAID MAGNETIC PORTIONS OF SAID CASE; A MOTOR FIELD COIL DISPOSED ABOUT A SECOND AXIS DISPLACED FROM SAID FIRST AXIS, SAID FIRST AND SECOND MAGNETIC PORTIONS OF SAID CASE BEING CONNECTED BY MAGNETIC MATERIAL TO FIRST AND SECOND SPACED POINTS; RESPECTIVELY, IMMEDIATELY ADJACENT AND MAGNETICALLY COUPLED TO OPPOSITE ENDS OF SAID FIELD COIL SO THAT WHEN SAID FIELD COIL IS ENERGIZED BY A.C. POWER THE ALTERNATING MAGNETIC FIELD CREATED THEREBY IS COUPLED BY SAID MAGNETIC PORTIONS OF SAID CASE TO SAID POLE PIECES SO AS TO ROTATE SAID ROTOR; SAID GEAR TRAIN, SAID INTERVAL TIMING MEANS, SAID ROTOR, SAID POLE PIECES, AND SAID FIELD COIL ALL BEING MOUNTED UPON AND SUBSTANTIALLY WITHIN SAID CASE AND BETWEEN SAID WALLS, WHEREBY SAID CASE SERVES TO MOUNT AND ENCLOSE THE COMPONENT PARTS OF THE TIMER AND ALSO FUNCTIONS AS A PORTION OF THE ELECTROMAGNETIC MOTOR.