US 3578923 A
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United StatesPatent 2,055,7o7 9/1936 Rippl  Inventors Fred E. Morey, III;
George B. Mork, Baraboo, Wis ] Appl. No. 791,702  Filed Jan. 16, 1969  Patented May 18, 1971  Assignee Gulf & Western Industries New York, N.Y.
 ELECTROMAGNETICALLY CLUTCHED RESET TIMER 13 Claims, 5 Drawing Figs.  US. Cl 200/38, 335/74  Int. Cl H0lh 7/08, HOlh 43/10, HOlh 3/32  Field ofSearch 200/38, 180; 335/30, 59,64, 65, 150, 121, 75; 335/74  References Cited UNITED STATES PATENTS 2/1955 Droell 335/59X 2,928,916 3/ 1960 Bonanno 335/59X 3,036,174 5/1962 Ardia et a]. 335/75 3,293,385 12/1966 Travaglio 200/38(E) 3,308,406 3/1967 Barnhart 335/74 Primary Examiner-Robert K. Schaefer Assistant Examiner-J. R. Scott Attorney-Meyer, Tilberry and Body ABSTRACT: An adjustable reset timer comprising: a frame, a motor, and electromagnetic clutch assembly, drive means for interconnecting said motor and said clutch assembly, a clutch armature axially movable into and out of magnetically locked engagement with said clutch assembly and adapted to rotate in an operative direction from an initial preselected position to a final position, at least one switch affixed to said frame at a point corresponding to said final position, means for actuating said switch when said armature is in said final position, and means for selecting the initial position.
Patented May 18, 1971 I I 3,578,923
I 2 Sheets-Sheet 1 FIG.2
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ELECTROMAGNETICALLYCLUTCIIED RESET TIMER This invention pertains to the timer art and more particularly to a timer having an electromagnetic clutch.
The invention is particularly applicable to an adjustable reset timer for controlling a process and will be describcr with particular reference thereto; however, it will be appreciated that the invention has broader application and may be used in conjunction with a variety of devices which require a timed cycle as part of their operation.
It is well known in the prior art to provide a reset timer comprising a frame, a synchronous motor, a clutch armature adapted to rotate through a preselected timingcycle and actuate a switch for controlling a process, drive means extending from the motor rotating the clutch armature and a clutch means for coupling the drive means to the clutch armature. Heretofore, the clutch means has ordinarily taken the form of a relay solenoid or gear train. Furthermore, it has'been'the practice to maintain the clutch means as a separate cornponent of the timer, and "as such it was generally removed from the actual drive means and an arm or similar device employed to engage or disengage the drive means.
Reset timers of the type heretofore described have had undesirable characteristics which has restricted their application. One of the principal problems with a reset timer of this type is a tendency toward timing inaccuracies caused by the clutch means. Furthermore, accurate processcontrol has been limited in view of the type of switch used to regulate the control circuitry. Lastly, problems have been encountered in preventing the timing cycle from varying during operation due to a lack of any means for locking the'length ofthe timing cycle.
The present invention contemplates a new and improved device which overcomes all of the above-referred problems and provides an electromagnetically clutched reset timer which has a high degree of accuracy and is long lasting.
In accordance with the present invention there isprovided an adjustable reset timer comprising a frame, a synchronous motor, and an electromagnetic clutch assembly having a case, a magnetic coil and a rotor. A drive means is provided for connecting the motor to the rotor, the drive means being integral with the clutch assembly and adapted to rotate the rotor iridependently of the case and coil. Additionally there is means for securing the case and coil to the frame to prevent rotation of the case and coil when the drive means is rotating. A clutch armature is coaxially disposed about the drive means and adapted to rotate in an operative direction from a selectable predetermined position to a fixed final position; the clutch armature being axially movable into and out of magnetically locked engagement with the rotor, whereby the clutch armature and rotor are rotatable in unison in the operative direction when the coil is energized. At least one switch is affixed to the frame at a point corresponding to the final position, whereby actuation of the switch is determinative of the completion of a preselected timing cycle. An actuator means is provided adjacent the clutch armature and adapted to rotate therewith for actuating the switch when the armatureis in the final position. A reset stop means is coaxially disposed-about the drive means adjacent the actuator means and angularly adjustable for selecting the predetermined position. There is further provided means for biasing the clutch armature and actuating means in a direction opposite to the operative direction and toward the reset stop means.
The principal object of thepresent invention is to provide an electromagnetically clutched reset timer having a high degree of timing accuracy.
Another object of the present invention is to provide a electromagnetically clutched reset timer wherein the motor is not subject to damage as'a result of continuous operation.
A further object of the present invention is to provide an electromagnetically clutched reset timer possessing rapid switching capabilities.
A still further object of the present invention is to provide an electromagnetically clutched reset timer having-a timing cycle which will not vary during operation.
An additional object of the invention is to provide an electromagnetically clutched reset timer which is easy and economical to manufacture.
The invention may take physical form in certain parts and arrangements of parts, a preferred embodiment of which will be described in detail in this specification and illustrated in the accompanying drawings which form a part hereof and wherein:
FIG. I is a pictorial view of an electromagnetically clutched reset timer according to the present invention;
FIG. 2 is an enlarged side elevation view of the subject invention, partially broken away, showing the electromagnetic clutch in detail;
FIG. 3 is a top view of the subject invention;
FIG. 4 is a cross section view taken on line 4-4 of FIG. 3 showing the actuator means in the predetermined position; and,
FIG. 5 is a cross section view taken on line 4-4 of FIG. 3 showing the actuator means in the final position.
Referring now to the drawings wherein the showings are for the purpose of illustrating the preferred embodiment of the invention only and not for the purpose of limiting same, FIG. I shows the overall arrangement'of an adjustable reset timer, referred to generally by the reference letter A, having a frame structure B, a synchronous motor C, and an electromagnetic clutch assembly D.
Referring specifically to FIGS. 1 and 2, wherein the structural components of the reset timer A are illustrated and will now be described in detail. The frame structure B is generally U-shaped, having a mounting plate 10 and upper and lower flanges 12a and 12b, respectively, integral therewith and projecting rearward therefrom. Affixed to the rear face of the mounting plate 10, by means of fasteners 14, is a synchronous motor C. Mounted on theunderside of the upper flange 12a is a full wave bridge rectifier 16 for converting the alternating current supplied by a power source (not shown) to direct current.
Projecting forward from the front face of the mounting plate 10 are two upper spacers 18a and two lower spacers 18b which have secured to their forwardmost ends, by means of screws 20, a faceplate 22. The two lower spacers 18b are comprised of two' segments each which have suspended between them a generally arcuate terminal block 24. A plurality of screw-type electrical contacts 26 are disposed on the terminal block 24 and raised insulator barriers 28 are provided intermediate the contacts. The terminal block 24 furnishes the means for connecting the timer A to both the power source (not shown) and the processes (not shown) which it is controlling. Furthermore, the electrical circuitry which controls the various components of the timer A, such as rectifier leads 34, similarly are connected to the terminal block 24.
As best shown in FIG. 2,- disposed intermediate the mounting plate 10 and the faceplate 22 is an electromagnetic clutch assembly D having'a case 36, a coil 38 and a rotor 40. In accordanc'e'with the present invention there is provided a drive meansfor interconnectingthe motor C and the rotor 40 which may take a number of forms, however in the preferred embodiment of the invention this takes the form of a rnotor shaft 42 which extends through an opening in the mounting plate 10 and terminates in the region of the faceplate 22 and is adapted to rotate in an operative direction as designated by the arrow x of FIG. 1. The rotor is configured to have a contact face 44 at its forwardmost end and a rotor shaft 46 axially integral therewith. The rotor 40 has an annular opening axially disposed therein which allows it to be slidably mounted on the motor shaft 42 and secured thereto for rotations therewith by means of a setscrew 48. It can therefore be seen that when the motor C and motor shaft 42 are rotating in the operative direction, the rotor 40 is also rotating in the same direction andat the same rate of speed. 7
Coaxially' supported on the rotor shaft 46 by means of bearings 54 are the case 36 and the coil 38 of the clutch assembly-D, the axial movement thereof on the shaft being limited by a retaining ring 56 mounted on the shaft. Power is" supplied to the coil 38 for purposes of energiration by means of wires 58 which connect the coil to the rectifier 16. As shown in FIG. 3, the case 36 has a tab 60 which extends outwardly therefrom and engages a pin 62 which is affixed to the front face of the mounting plate It] and projects forwardly therefrom. In view of the foregoing structural configuration, it
is readily apparent that when the motor shaft 42 and consequently the rotor 40 are rotating, the case 36 and the coil 38 remain stationary.
Referring now to FIGS. 2 and 3, there is provided a clutch armature referred to generally by the reference letter B, adapted to rotate in the operative direction from a selectable predetermined position to a fixed final position, and comprising a square hub 64 coaxially disposed and free to rotate about the shaft 42, and a disc 66 having a square opening at its midpoint and adapted to be slidably mounted on the hub for rotation and therewith. The disc 66 is adjacent the contact face 44 of the rotor 40 and axially movable into and out of magnetically locked engagementtherewith. When the coil 38 is energized the disc 66 is magnetically locked to the contact face 44, whereby the disc and consequently the hub 64 rotate in unison with the rotor40 in the operative direction.
In accordance with the present invention there is provided an actuator means which may take many forms, however, in the preferred embodiment it takes the form of an actuator arm support 68 secured to the hub 64 for rotation therewith and extending radially outward therefrom, and an actuator arm 70 integral with the actuator arm support and projecting substantially perpendicular thereto in a rearward direction. Since the actuator means is alTixed to the hub 64, whenever the clutch armature E rotates in the operative direction it follows that the actuator means will similarly so rotate from the predetermined position to the final position, thereby defining an arc of rotation.
Affixed to the front face of the mounting plate at a point corresponding to the final position are a pair of snap action switches, referred to as first switch 76 and second switch 78. It is to be appreciated that any number and type of switches may be employed depending upon the processes to be controlled and the mode of actuation desired. It is to be further appreciated that the switches 76, 78 may be actuated either simultaneously or at different time intervals. Switch actuation is accomplished by means of first and second actuating screws 80 and 82, respectively, which are carried by the actuator arm 70. The actuating screws 80, 82 pass through threaded holes in the actuator arm 70 and are longitudinally adjustable relative to one another. If the actuating screws are adjusted so that the first screw 80 projects outward from the actuator arm 70 a distance greater than that of the second screw 82, the first switch 76 will be actuated before the second switch 78. It is therefore possible to adjust the subject invention so as to provide a time lag between the actuation of switches.
In accordance with the present invention there is provided a setting ann means for selecting the predetermined position, this may take many forms, however, in the preferred embodiment it is comprised of a reset stop shaft 84, a reset stop arm 86 and a selector knob 88. The reset stop shaft M is coaxial with the motor shaft 42 and passes through an opening in the faceplate 22. An annular opening in the rearward portion of the shaft 84 is the terminus point for the motor shaft 42. Af-
fixed to the shaft 84 and projecting radially outward therefrom, and intermediate the faceplate 22 and actuator means, is the reset stop arm 86 which is angularly adjustable for selecting the predetermined position. The reset stop arm 86 is generally L-shaped, and has its base projecting substantially rearward to intersect the arc of rotation defined by the actuator arm 70. The selector knob 88 is secured to the reset stop shaft 84 on the forward side of the faceplate 22 and facilitates the angular adjustment of the reset stop arm 86. A cover plate 92 having an arcuate scale graduated in increments of time is mounted adjacent the forward side of the faceplate 22 and secured thereto by screws 20. The selector knob 88 has a pointer 94 projecting radially outward therefrom (as shown in FIG. 1) which may be aimed toward the desired timing cycle as indicated on the scale.
There is provided a means for biasing the clutch armature E and actuator means in a direction opposite to the operative direction and toward the reset stop arm 86. The biasing means may take numerous forms, however, in the preferred embodiment it is shown as a spring having one end affixed to the hub 64 and the other end afiixed to the reset stop arm 86. When the selector knob 88 and consequently the reset stop arm 86 are set at the predetermined position, the spring 100 causes the actuator arm 70 and actuator arm support 68 to be in contact with the reset stop arm and thus in the predetermined position (as best shown in FIG. 3).
In accordance with the present invention there is provided a locking means, referred to generally by the reference letter F, for retaining the selector knob 88 in thepredetermined position when the reset stop means rotates from the predetermined position to the final position. The locking means F may take many forms, however, in the preferred embodiment it takes the form of a knurled knob 102 having a threaded stem 104 extending from the rear thereof and a washer 106 coaxi' ally disposed on the stem and adjacent the knob. The stem 104 passes through the cover plate )2 and is retained in a threaded hole in the faceplate 22, thereby making it longitudinally adjustable. in this position the knurled knob 102 and washer 106 overlap the edge of the selector knob 88. By turning the knurled knob 102 in a direction which reduces the distance between it and the cover plate 22, it becomes possible to exert a compressive force on the edge of the selector knob 88, whereby the selector knob is prevented from rotating. It can therefore be seen that once the predetermined position is selected and the selector knob 88 locked in this position by the locking means F, the predetermined position cannot vary during the timers operation, thereby assuring accurate repetitive timing cycles.
Referring now to FlGS. l, 4, and 5, wherein the operation of the adjustable reset timer A will be described in detail. Assume, for purposes of explanation, that it is desired to control a process which is to be turned on, run for a selected time interval, and then be shut off. Further assume that the desired time interval is 20 seconds, although it is to be appreciated that any interval may be used. The locking means F is released by turning the knurled knob 102 and the selector knob 88 is rotated until its pointer 94 is aimed toward the 20" on the graduated timing scale of the cover plate 92 (as best shown in H6. 1). The locking means F is then secured to assure that this setting will not vary during the timers operation. Setting the selector knob 88 at 20" similarly sets the reset stop arm 86, thereby establishing the predetermined position. The spring H00 causes the actuator arm 70 to be in contact with the reset stop arm 86 and therefore also in the predetermined position (see F IGS. 3 and 4).
Power is supplied to the timer through an external switch (not shovm). When the contacts of the external switch are closed, the process which is being controlled is turned on and the synchronous motor C begins to rotate in the operative direction thereby driving the motor shaft 42 and rotor 40 also in the operative direction. At the same point in time, power is also being applied to the rectifier 16 which converts the AC current to DC and energizes the coil 38 of the electromagnetic clutch assembly D. The energization of the coil 38 creates a magnetic field in the rotor 40 which axially attracts the disc 66 of the clutch armature E toward the contact face 44 of the rotor. The magnetic field is sufficiently great to create a static friction which binds the disc 66 into magnetically locked engagement with the rotor 40. Since the motor C, motor shaft 42 and rotor 40 are rotating in the operative direction, this magnetic engagement causes the clutch armature E and consequently its components, ,he disc 66 and hub 64, to also rotate in the operative direction. The actuator arm support 68 is secured to the hub 64, as such rotation of the hub causes the actuator arm support and the actuator am 70 to rotate. Bear in mind that the rotation heretofore discussed commences from the predetermined position, as shown in FIG. 4, and proceeds in the operative direction until the final position is reached, as shown in FIG. 5, thereby defining a timing cycle.
The motor C continues to drive and the actuator arm 70 continues to rotate causing the first actuating screw 80 to come in contact with the first actuating lever 108 of the first switch 76. Further rotation of the actuator arm 70 until the final position is reached causes the first actuating screw 80to depress the first actuating lever 108, thereby actuating the first switch 76 which in turn shuts off the process which is being controlled by the timer A. The second actuating screw 82, which is longitudinally adjustable relative to thefirst adjusting screw 80, is so adjusted that it does not depress the second actuating lever 110 at the same instant as does the first actuating screw, and as such, the second switch 78 remains unactuated at this point in time (as shown in FIG; 5). The motor C continues to drive beyond the final position in the operative direction for a short interval of time until a stop position is reached, this position being defined by the'fact that the second actuating screw 82 depresses the second actuating lever 110 thereby actuating the second switch 78. During this entire operation the reset stop arm 86 has remained fixed due to the locking means F. The second switch 78 is connected to the motor C, and its actuation deenergizes the motor and prevents any further rotation of the motor shaft 42. Deenergization of the motor C is a beneficial feature which minimizes motor wear and reduces the likelihood of motor damagcfltis to be appreciated that any number and type of switches may be employed and that the operations controlled by them may vary. Thus, for example, it would be possible to use two switches, each of which controlled a separate process. ln the preferred embodiment snap action switches have been used because they assure a high degree of timing accuracy due to instantaneous contact closure and pressure. Furthermore, these switches could be actuated simultaneously or at different points in time.
The timer A will remain in the aforementioned position; namely, process shut off and motor deenergized, so long as the contacts of the external switch remain closed. This results from the fact that power is still being supplied tothe electromagnetic clutch D, even though the motor C has been deenergized, thereby retaining the actuator arm 70 in the stop position. When the contacts of the external switch are opened, the coil 38 is deenergized and the magnetic engagement between the rotor 40 and clutch armature E ceases. The spring 100 causes the clutch armature E, actuating arm support 68 and actuating arm 70 to be biased in a direction opposite to the operative direction, and to rotate these components back to the predetermined position. Thus, the actuating arm 60 comes to rest on the reset stop arm-86, as shown in FIG. 4. Thetimer A is now ready to commence another timing cycle.
' selected interval, and then turned on, comprising:
a. a frame structure;
I b. a synchronous motor;
c. an electromagnetic clutch assembly having a case, a coil and a rotor;
(1. drive means for interconnecting said motor and said rotor;
e. said drive means being integral with said clutch assembly and adapted to rotate said rotor independently of said case and said coil;
f. means for securing said case and said coil to said frame to prevent rotation of said case and coil when said drive means is rotating;
g. a clutch armature coaxially dispose about said drive means and adapted to rotate in an operative direction from a selectable predetermined position to a fixed final position;
h. said clutch armature being axially movable into and out of magnetically locked engagement with said rotor, whereby said clutch armature and said rotor are rotatable in unison in said operative direction when said coil is energized;
i. at least one switch affixed to said frame at a point corresponding to said final position, whereby actuation of said switch is determinative of the completion of a preselected timing cycle;
j. actuator means adjacent said clutch armature and adapted to rotate therewith for actuating said switch when said armature is in the final position;
k. reset stop means coaxially disposed about said drive means adjacent said actuator means and angularly adjustable for selecting the predetermined position; and
l. means for biasing said clutch armature and actuator means in a direction opposite to the operative direction and toward said reset stop means.
2. The device defined in claim 1, wherein first and second snap action switches are affixed to said frame and located at a point corresponding to said final position.
3. The device defined in claim 2, wherein said actuator means includes first. and second actuating screws, longitudinally adjustable relative to one another, for actuating said first and second switches respectively at different points in time.
4. The device defined'in claim 3, further including first and second circuit means connected to said first and second switches respectivclyfor controlling processes.
'5. The device defined in claim 3, wherein said first actuating screw extends outward from said actuator means a distance greater than the distance which'said second actuating screws extends, for providing a time lapse between the actuation of said first switch and the actuation of said second switch.
6. The device defined in claim 5, wherein said second switch is connected to said motor, whereby upon the actuation of said second switch said motor is deenergized causing said motor and drive means to cease to rotate in said operative direction.
7. The device defined in claim 1, wherein a selector knob and timing scale are provided for angularly regulating said reset stop means to select the predetermined position.
8. The device defined in claim 7, wherein locking means is provided for retaining said selector knob in the predetermined position when said reset stop means rotates from said predetermined position to said final position.
. 9. The device defined in claim 1, wherein a terminal block is provided for connecting said reset timer to a power source and to said processes which are being controlled.
10. A reset timer adjustable to permit variable operative time sequences for controlling a controllable device, said timer comprising:
a magnetic clutch assembly including a coil and a rotor havinga longitudinal axis, said rotor including means for permitting independent rotation from said coil about said axis and further including a radially extending first contact-surface;
a clutch armature adjacent said assembly and coaxial therewith; said armature including means for permitting rotation of said armature coextensive with said clutch assembly and aradially extending second contact surface;
means for selectively shifting said clutch armature between a first position wherein said first and second contact surfaces are in a spaced-apart relationship and a second position wherein said first and second surfaces are in engaging contact;
means for rotating said armature when it is in said first position to a preselected variable arcuate position whereby the length of a predetermined time cycle is determined;
means for rotationally driving said rotor and said armature when said armature is shifted into said second position;
switch means for controlling energization or deenergization ofsaid controllable device; and,
means to provide actuation of said plurality at variable instants.
13. The reset timer as defined in claim 10 wherein said means for selectively shifting said clutch armature comprises energizing said coil to establish a magnetic force which axially forces said armature from said first position to said second position whereby said first and second surfaces are in engaging magnetic contact, and deenergizing said coil to permit said armature to return to said first position.