US1545728A - Time-controlled electric-switch system - Google Patents

Time-controlled electric-switch system Download PDF

Info

Publication number
US1545728A
US1545728A US683779A US68377923A US1545728A US 1545728 A US1545728 A US 1545728A US 683779 A US683779 A US 683779A US 68377923 A US68377923 A US 68377923A US 1545728 A US1545728 A US 1545728A
Authority
US
United States
Prior art keywords
rings
contact
time
hands
terminal
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US683779A
Inventor
Beck Carl Herman
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Priority to US683779A priority Critical patent/US1545728A/en
Application granted granted Critical
Publication of US1545728A publication Critical patent/US1545728A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • GPHYSICS
    • G04HOROLOGY
    • G04CELECTROMECHANICAL CLOCKS OR WATCHES
    • G04C23/00Clocks with attached or built-in means operating any device at preselected times or after preselected time-intervals
    • G04C23/14Mechanisms continuously running to relate the operation(s) to the time of day
    • G04C23/18Mechanisms continuously running to relate the operation(s) to the time of day for operating one device at a number of different times
    • G04C23/20Mechanisms continuously running to relate the operation(s) to the time of day for operating one device at a number of different times with contacts operated, or formed by clock hands or elements of similar form

Definitions

  • This invention relates to the time controlling, or predetermining, or periodic operation of electric circuits for any purpose whatever, either for direct operation of various electrically actuated devices or for the closing or opening of other and heaiier circuits, valves, etc., for effecting the operation desired.
  • My invention is applicable for use in connection with any form of actuating mecha nism having a dire-ct or proportional move-' ment with the hourly division of time and principally in association with a clock dial, preferably on the face thereof or in connection with other time mechanisms either mechanically or electrically driven or controlled by a central or master clock mechanism.
  • the principal objects of my invention are to effect a system of electrical switch control which will be exceedingly elastic in its application to industrial or scientific re.- quirements, one in which a great variety of control can be secured with comparatively simple control units and which maybe combined to secure the more complex controls necessary in order to carry out certain pre determined orders of mechanical or electriv cal functioning.
  • Figure 1 is a diagrammatic drawing showing a. connected series of horological devices having various speed relations to any desired time unit, and a plurality of the devices equipped with the different modifications of my circuit controlling mechanisms.
  • Figure 2 is an enlarged plan view of one of the devices showing a plurality of my contact rings cooperating with two rotating arms.
  • Figure 3 is an enlarged sectional elevation of the rings, arms and-contacting devices: and Figure 4 is a still larger sectional perspective view of a portion of the double or stepped ring of Figure 3.
  • Figures 5 and 6 are modifications 1n the interchangeable contacting terminals; and Figure 7 shows a variation in the means for positioning the terminals.
  • Figures 8 and 9 are schematic views showing the" application of my controlled circuits for stopping or starting a device.
  • Figures 10 andll show two of any number of circuit diagrams possible to employ with any set of contact rings.
  • FIG. 1 the diagram represents a series of clock mechanisms or dials (1), (2), (3), (4), and (5), any one of which may be considered as the master device or clock, in this case assumed to be the central one (1)- and each dial having one or more arms or revolving hands as indicated, and the master clock a pendulum.
  • the mechanism of'the master clock- may be either a spring or weight operated device
  • the arious overlapping dotted circles denoting gears are in different planes so as to avoid mechanical interference and all marked 72. correspond to.wha.t ordinarily operate the hour hands in clocks making one revolution every twelve hours, those marked m to the minute'hand gears and those marked 8 to the second hand gears.
  • any number of operative dials may be projected from the master dial by the use of intermediate gear wheels as shown, either to obtain a working dial having a second, minute, or hour hand only, or having both a minute and hour hand as indicted in the two dials to the right. Also, the direction of revolution is optional, depending on the number of intermediate gears.
  • each dial represents my contact rings and upon or through any one or combination of which the circuits I spaced relation of the arms cooperating with various contacting devices.
  • the arms are marked S, M orH on the various dials to designate second, minute or hour as the casemay be; and at (6) is indicated a device actuated by a circuit controlled from any of the dials for throwing v the dial into or out of operative re1a and (8).
  • the rings are provided with proper spaced holes (10) into which they may be inserted, and the arms or hands H, M are provided at the ends or other desired position with more or less resilient wipers (11) for wiping over the terminals, also, on either. or both-arms a flange (12) for making other contacts.
  • the terminal (8) shows a flat resilient contacting element (.8) projecting from it and of course may be positioned in a hole 'to take advantage of this resiliency or placed in the opposite plane.
  • the duration of an electrical contact depends on the length of the resilient contacting member and is repeated upon each revolution of the arm which makes it, whereas terminal (7 has a pivoted upper portion (7) which if presented inthe proper position is turned down by the movinghand in closing the contact and remains down, thus making but a single contact without repetition.
  • Contact (9) has a similar function to terminal (7 but provides for a long contact even without a resilient member, and operates as shown in Figure 3, being pivoted from a counterbalancing lever (13) fulcrumed by booking over a wire or pin (14) in one of any number of slots in the edge of ring (15), and having its lower end bent outwardly to engage any of the holes (19) or (20) in the stepped ring (16).
  • the wiper If enga ed with holes (19) it becomesrthe stationary e ement' of a wiping contact from the resilient wipers (11), but if placed in a hole (20) which is slotted over a vertical opening (21), the wiper first makes an electrical contact then moves the device bodily to the end of the slot, at which time the counterweighted arm (13) lifts the terminal entirely clear of the arm M.
  • the terminal (9) maybe used with the hour arm H by simply having the hour arm the longest of the two and preferably in the upper position.
  • rings are insulated a'single arm may throw them into electrical contact, or different sets of rings, as there may be any number of rings. Also one arm may be making a long wipingcontact while the other is making short intermittent contacts so that an unlimited number of combinations can be produced.
  • a series of levers might be .arranged [around the dials for simple pressing upon to project a terminal contact out of the ring frombelow, as indicated in Figure 7 wherein the necessary elements are shown in as sociation with one terminal to make such an arrangement operative,the lever (22) being pivoted to the dial at (23) and having ,a finger key (24), with the other end connected to or arranged for lifting a terminal 28) to project above the ring (17) or (18).
  • t (25) is indicated a suitable friction stop or look for holding the lever at either extreme position.
  • FIGS. 8 and 9 illustrate my method of stopping and starting a device, either a machine or a similar horological mechanism having a pendulum (26) swinging normally to the maximum position shown in Figure 8.
  • the pendulum rod made of iron will be drawn beyond its maximum travel and locked by a snap pawl (28) shown in Figure 9 so that it cannot return after breaking the circuit.
  • This latter Figure 9 is an enlarged section of aportion of Figure 8 taken along the line v99 and shows the pendulum rod (26) locked by the pawl, pulled into the path of the rod by the other end of the magnet (27).
  • Pin jacks (34) lead to the telephone or call bells in the various rooms.
  • Pin jacks (35) are used when more than one room is to receive a call at the sametime.
  • Modern pinjac switchboards could be used employing eit r metallic or ground return circuits.
  • pin-jack (36) In using pin-jack (36) the sides are connected' to the rings and if conductor terminals are set in the rings the circuit would be completed through (36) at the intervals of time determined by the setting. )Vhen so used it is of course necessary to have both rings of conducting material, and insulated frompne another as well as from the hands.
  • the system embraces a series of variously timed elements for making or breaking any combination of electrical contacts.
  • the operations may be predetermined many hours, or minutes, or reduced to second intervals by use of the various, or combinations of the various S, M or H arms. Also,
  • an electrical contact terminal adaptcdto be temporarily engaged for electrical contact by the rotating element and rendered inactive for further electrical contact by the movement of'the element.
  • an electrical contact terminal adapted to be engaged by the rotating element, said element having a pivoted contact portion adapted to be swung out of the path of travel of the element and beyond the point of any further contact therewith upon be ing moved by the element.
  • an electrical contact terminal adapted to be engaged by the rotating element for making an electrical contact therewith, saidterminal having a pivoted contact portion adapted to be swung out of the path of travel of the element upon being moved by the element, and means for swinging it entirely clear of the path of travel to positively avoid further contact with the element upon its next rotation.
  • electrical contact terminal adapted to be engaged by the rotating element, and a stepped ring surrounding the rotating elementhaving means in both steps for selectively positioning said terminal therearound, the means in one step affording a fixed hold of the terminal for successive contacting, and in another step a tripping hold for re lease of the terminal after contacting.
  • a plurality of concentric rings on the dial under the hands adapted for the positioning therein of a-plurality of electrical contact devices for selective engagement with the hands, one of the rings presenting the devices for successive cont-acting and another for nonsuccessive contacting.
  • Means for controlling a plurality of circuits comprising a clock dial with a pair of rotating hands thereover, means over which the hands rotate for establishing an electric circuit at a. predetermined time, said means being actuated by engagement with a rotating hand or hands, and similarly positioned means actuated by a and or hands for breaking the circuit at a predetermined time interval.
  • Means for controlling a plurality of electrical circuits for starting and stopping a machine comprising a clock dial with a pair of rotating hands thereover adapted to establish short period electrical circuits at spaced predetermined time intervals, a swinging member on the machine having a normal path of travel, an electro-magnet energized by one of the circuits for drawing the swinging member beyond its normal path, a locking device for .retaining the swinging member in such position, and an electromagnet energized by a later controlled circuit for releasing the locking device.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Rotary Switch, Piano Key Switch, And Lever Switch (AREA)

Description

July 14, 1925. C. H. BECK T'IME CONTROLLED ELECTRIC SWITCH SYSTEM Filed Dec. 51, 1923 3 sheets sh et 1 "I I6 i 09 01 FL HERMAN BECK July 14, 1925. 1,545,728 c. H. BECK TIME CONTROLLED ELECTRIC SWITCH SYSTEM Filed D80. 51. 1923 3 sheets -sh e t 2 mumm July 14, 1925. 1,545,728
C. H. BECK TIME CONTROLLED ELECTRIC SWITCH YSTEM FiledDec. 31, 1925 3 Sheets- She'et 3 aga H 1; gnue'nlo'o Cm: HERMAN BEc/r dnonuzq Patented July 14, 1925.
UNITED STATES CARL HERMAN BECK, OF SAN FRANCISCO, CALIFORNIA.
TIME-CONTROLLED ELECTRIC-SWITCH SYSTEJIL,
Application filed December 31, 1923. Serial No. 683,779.
To all whom it may concern Be it known that I, CARL HERMAN BECK, a citizen of the United States, and a resident of San Francisco, county of San Francisco, State of California,-have invented a new and useful Time-Controlled Electric- Switch System, of which the following is a specification.
This invention relates to the time controlling, or predetermining, or periodic operation of electric circuits for any purpose whatever, either for direct operation of various electrically actuated devices or for the closing or opening of other and heaiier circuits, valves, etc., for effecting the operation desired.
My invention is applicable for use in connection with any form of actuating mecha nism having a dire-ct or proportional move-' ment with the hourly division of time and principally in association with a clock dial, preferably on the face thereof or in connection with other time mechanisms either mechanically or electrically driven or controlled by a central or master clock mechanism.
The principal objects of my invention are to effect a system of electrical switch control which will be exceedingly elastic in its application to industrial or scientific re.- quirements, one in which a great variety of control can be secured with comparatively simple control units and which maybe combined to secure the more complex controls necessary in order to carry out certain pre determined orders of mechanical or electriv cal functioning.
I realize the objects outlined in the system and apparatus illustrated in the drawings, and in which Figure 1 is a diagrammatic drawing showing a. connected series of horological devices having various speed relations to any desired time unit, and a plurality of the devices equipped with the different modifications of my circuit controlling mechanisms.
Figure 2 is an enlarged plan view of one of the devices showing a plurality of my contact rings cooperating with two rotating arms.
Figure 3 is an enlarged sectional elevation of the rings, arms and-contacting devices: and Figure 4 is a still larger sectional perspective view of a portion of the double or stepped ring of Figure 3.
Figures 5 and 6 are modifications 1n the interchangeable contacting terminals; and Figure 7 shows a variation in the means for positioning the terminals.
Figures 8 and 9 are schematic views showing the" application of my controlled circuits for stopping or starting a device.
Figures 10 andll show two of any number of circuit diagrams possible to employ with any set of contact rings.
Before going into constructional detail it might be stated that my invention is not limited to any fixed relation or numberof elements shown in the drawing or arrangements of circuits employed with them, as any number of variations are possible and will be apparent to a person skilled in the art.
In Figure 1 the diagram represents a series of clock mechanisms or dials (1), (2), (3), (4), and (5), any one of which may be considered as the master device or clock, in this case assumed to be the central one (1)- and each dial having one or more arms or revolving hands as indicated, and the master clock a pendulum.
The mechanism of'the master clock-may be either a spring or weight operated device,
or electro-magnetically controlled by another remote clock as may be desired, but
since the clock mechanism per se forms no part of my invention it is not detailed in the drawings, but only the necessary functioning elements to illustrate the inventionnre shown, such as the main gears, arms, contact rings, terminals, etc.
The arious overlapping dotted circles denoting gears are in different planes so as to avoid mechanical interference and all marked 72. correspond to.wha.t ordinarily operate the hour hands in clocks making one revolution every twelve hours, those marked m to the minute'hand gears and those marked 8 to the second hand gears.
Any number of operative dials may be projected from the master dial by the use of intermediate gear wheels as shown, either to obtain a working dial having a second, minute, or hour hand only, or having both a minute and hour hand as indicted in the two dials to the right. Also, the direction of revolution is optional, depending on the number of intermediate gears. r
The heavy circles on each dial represent my contact rings and upon or through any one or combination of which the circuits I spaced relation of the arms cooperating with various contacting devices.
The arms are marked S, M orH on the various dials to designate second, minute or hour as the casemay be; and at (6) is indicated a device actuated by a circuit controlled from any of the dials for throwing v the dial into or out of operative re1a and (8).
To receive any of these contacts the rings are provided with proper spaced holes (10) into which they may be inserted, and the arms or hands H, M are provided at the ends or other desired position with more or less resilient wipers (11) for wiping over the terminals, also, on either. or both-arms a flange (12) for making other contacts.
The terminal (8) shows a flat resilient contacting element (.8) projecting from it and of course may be positioned in a hole 'to take advantage of this resiliency or placed in the opposite plane.
The duration of an electrical contact depends on the length of the resilient contacting member and is repeated upon each revolution of the arm which makes it, whereas terminal (7 has a pivoted upper portion (7) which if presented inthe proper position is turned down by the movinghand in closing the contact and remains down, thus making but a single contact without repetition.
Contact (9) has a similar function to terminal (7 but provides for a long contact even without a resilient member, and operates as shown in Figure 3, being pivoted from a counterbalancing lever (13) fulcrumed by booking over a wire or pin (14) in one of any number of slots in the edge of ring (15), and having its lower end bent outwardly to engage any of the holes (19) or (20) in the stepped ring (16). If enga ed with holes (19) it becomesrthe stationary e ement' of a wiping contact from the resilient wipers (11), but if placed in a hole (20) which is slotted over a vertical opening (21), the wiper first makes an electrical contact then moves the device bodily to the end of the slot, at which time the counterweighted arm (13) lifts the terminal entirely clear of the arm M.
The terminal (9) maybe used with the hour arm H by simply having the hour arm the longest of the two and preferably in the upper position.
or common return for one or anynumber of c rcuits.
If the rings are insulated a'single arm may throw them into electrical contact, or different sets of rings, as there may be any number of rings. Also one arm may be making a long wipingcontact while the other is making short intermittent contacts so that an unlimited number of combinations can be produced.
Instead of placing contact terminals of the type (7) or (8) into the holes (10) by hand, a series of levers might be .arranged [around the dials for simple pressing upon to project a terminal contact out of the ring frombelow, as indicated in Figure 7 wherein the necessary elements are shown in as sociation with one terminal to make such an arrangement operative,the lever (22) being pivoted to the dial at (23) and having ,a finger key (24), with the other end connected to or arranged for lifting a terminal 28) to project above the ring (17) or (18). t (25) is indicated a suitable friction stop or look for holding the lever at either extreme position.
The controlled circuits provided by my system may be used to accomplish any desired mechanical or electrical result, and Figures 8 and 9 illustrate my method of stopping and starting a device, either a machine or a similar horological mechanism having a pendulum (26) swinging normally to the maximum position shown in Figure 8. Upon energizing the electro-magnet (27) through one of the control circuits, the pendulum rod made of iron will be drawn beyond its maximum travel and locked bya snap pawl (28) shown in Figure 9 so that it cannot return after breaking the circuit. This latter Figure 9 is an enlarged section of aportion of Figure 8 taken along the line v99 and shows the pendulum rod (26) locked by the pawl, pulled into the path of the rod by the other end of the magnet (27). r v,
To.v release the pendulum and start the device arsecond controlled circuit is closed through the elec'tro-ma et (29) which will. attract the armature 30) .on the pivoted release rod (31) and thus throw the pawl. The release rod is held at either point by suitable resilient or frictional means as indicated at (32)l In Figures 10 and 11 illustrative clrcult iao 1,545,728 I v v arrangements controlled by my invention are shown, the former being the arrange- "ment as suited for a hotel or call alarm system., In this example the inner ring would be made of insulating material and the holes hushed with a conductor into which the contact terminals (7) "would be placed, each 1 bushing being connected to a pin jack (33). 'Pin jacks (34) lead to the telephone or call bells in the various rooms. Pin jacks (35) are used when more than one room is to receive a call at the sametime. Modern pinjac switchboards could be used employing eit r metallic or ground return circuits.
In using pin-jack (36) the sides are connected' to the rings and if conductor terminals are set in the rings the circuit would be completed through (36) at the intervals of time determined by the setting. )Vhen so used it is of course necessary to have both rings of conducting material, and insulated frompne another as well as from the hands.
' No circuit is established until both hands are in contact with their respective rings through the terminals set in the rings at the desired time position.
In regard to the diagram shown in Figi ure 11, this shows the arrangement for causing a machine such as (37) to function for' a definite time periodically and is easily understoodby any electrician. The circuit.
established by the hour hand on the inner ring serving to energize the coil of the machine (37) through the contacts of the looking relay (38), and when the minute hand makes a contact on the outer ring the clearout relay (39) breaks the circuit and re-establishes the original condition with the machine at rest.
In considering my invention it willbe seen that the system embraces a series of variously timed elements for making or breaking any combination of electrical contacts. The operations may be predetermined many hours, or minutes, or reduced to second intervals by use of the various, or combinations of the various S, M or H arms. Also,
for split second contacts further dials havrings (17) or (18) and adapted for various posltloning of either terminals (7 or (8) as indicated, and for operation by the passing pendulum in the same manner as by-the rotating arms; v
Having thus described my invention and illustrated its practical application, it will be seen to be one admitting of considerable modification. The principal feature is of course the arrangement of contacts, the multiple rings and revolving arms; but whether the rings are stationary or whether they revolve and the arms are stationaryor whether the rings are partially revolvable, etc., does not pass without the spirit of the invention, and any such modifications are intended to be covered in my appended claims. v
I claim:
1. In combination with a horological mechanism having a constantly rotating element, an electric circuit associated therewith and means actuatedby the rotating element for temporarily closing the circuit upon a rotation of the element through the element and of being inactive upon further rotations.
2. In combination with a horological mechanism having a constantly rotating element, an electric circuit associated therewith and means actuated by the rotating element for closing the circuit upon a rotation of the element, said means presenting an ac-' tive or inactive condition to a further rotation of the element depending on its initial setting.
3. In combination with a horological mechanism having a. rotating element, an electrical contact terminal adaptcdto be temporarily engaged for electrical contact by the rotating element and rendered inactive for further electrical contact by the movement of'the element.
4. In combination with a horological mechanism having a rotating element, an electrical contact terminal adapted to be engaged by the rotating element, said element having a pivoted contact portion adapted to be swung out of the path of travel of the element and beyond the point of any further contact therewith upon be ing moved by the element.
5. In combination with a horological mechanism having a rotating element, an electrical contact terminal adapted to be engaged by the rotating element for making an electrical contact therewith, saidterminal having a pivoted contact portion adapted to be swung out of the path of travel of the element upon being moved by the element, and means for swinging it entirely clear of the path of travel to positively avoid further contact with the element upon its next rotation.
6. In combination with a horological mechanism having a rotating element, an
electrical contact terminal adapted to be engaged by the rotating element, said element having a pivoted contact portion adapted to be swung out of the path of travel of the element upon being moved by the element, and a counterweight for swinging it clear of the path of travel.
&
electrical contact terminal adapted to be engaged by the rotating element, and a stepped ring surrounding the rotating elementhaving means in both steps for selectively positioning said terminal therearound, the means in one step affording a fixed hold of the terminal for successive contacting, and in another step a tripping hold for re lease of the terminal after contacting.
8. In combination with a clock dial having a pair of rotating hands, a plurality of concentric rings on the dial under the hands adapted for the positioning therein of a-plurality of electrical contact devices for selective engagement with the hands, one of the rings presenting the devices for successive cont-acting and another for nonsuccessive contacting.
9. Means for controlling a plurality of circuits comprising a clock dial with a pair of rotating hands thereover, means over which the hands rotate for establishing an electric circuit at a. predetermined time, said means being actuated by engagement with a rotating hand or hands, and similarly positioned means actuated by a and or hands for breaking the circuit at a predetermined time interval.
10. Means for controlling a plurality of electrical circuits for starting and stopping a machine comprising a clock dial with a pair of rotating hands thereover adapted to establish short period electrical circuits at spaced predetermined time intervals, a swinging member on the machine having a normal path of travel, an electro-magnet energized by one of the circuits for drawing the swinging member beyond its normal path, a locking device for .retaining the swinging member in such position, and an electromagnet energized by a later controlled circuit for releasing the locking device.
CARL HERMAN BECK.
US683779A 1923-12-31 1923-12-31 Time-controlled electric-switch system Expired - Lifetime US1545728A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US683779A US1545728A (en) 1923-12-31 1923-12-31 Time-controlled electric-switch system

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US683779A US1545728A (en) 1923-12-31 1923-12-31 Time-controlled electric-switch system

Publications (1)

Publication Number Publication Date
US1545728A true US1545728A (en) 1925-07-14

Family

ID=24745416

Family Applications (1)

Application Number Title Priority Date Filing Date
US683779A Expired - Lifetime US1545728A (en) 1923-12-31 1923-12-31 Time-controlled electric-switch system

Country Status (1)

Country Link
US (1) US1545728A (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3349685A (en) * 1963-08-19 1967-10-31 Werner W Buechner Photographic timer and method of timing photographic treating processes

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3349685A (en) * 1963-08-19 1967-10-31 Werner W Buechner Photographic timer and method of timing photographic treating processes

Similar Documents

Publication Publication Date Title
US2421986A (en) Alarm clock and switch
US2096620A (en) Time switch
US1545728A (en) Time-controlled electric-switch system
US2803300A (en) Electric timer
US2580787A (en) Impulse-actuated program device
US2489098A (en) Process timer
US2190832A (en) Preselector and remote control system
US2098965A (en) Clock
US1693721A (en) Clock-controlled switch
US2262471A (en) Selective electric switch apparatus
US2533877A (en) Radio time tuning device
US2342814A (en) Time control apparatus
US1841746A (en) Electric alarm clock
US2737236A (en) Timing mechanism
US2420019A (en) Timing device
US1841283A (en) Distant control equipment
US1964047A (en) Indicating dial for stock quotation boards
US1390907A (en) Automatic call system for hotels
US2071173A (en) Timer
US870900A (en) Time-controlled circuit-closing device.
US1951027A (en) Time switch
US1854643A (en) Radio period selecting device
US2565083A (en) Precision selector device
US2194034A (en) Time-controlled circuit selector
US2575699A (en) Electrical contactor