Abstract: A concealable surgical light device such as for a birthing room has a frame for supporting the light on one side and a decorative panel on the other side. The frame includes reinforcing ribs positioned in a Y shape, and a cylindrical section at the intersection of the ribs for attaching the light. The frame is rotatably supported inside a housing which is fixed within the ceiling structure. At one end of the housing there is a fixed tube and a bearing and at the other end is an output shaft of a speed reducer gear connected to the frame through a torque limiter and slip clutch for rotatably supporting the frame. Wires are fed through the tube without being subjected to rubbing or twisting. In a closed position of the frame, the light is concealed within the ceiling structure and the decorative panel is flush with the ceiling. In an open position, the light is deployable as it faces into the birthing room.

Abstract: Disclosed is a rotary lamp for stage lighting control, which utilizes a four-step control switch to control a long lamp and two short lamps which are respectively mounted on a revolving shaft of a seat to rotate at a constant speed.

Abstract: A remotely controlled security lighting system (10) that utilizes the common utility power lines of a building to provide communication between a master control/transmitting unit (12) and a plurality of remote light/receiving units (50). The unit (12) includes a light selector switch (16) that allows a particular light to be selected, a light power switch (18) that powers the selected light and a joystick (20) that positions the selected light in azimuth and elevation. The remote light/receiving unit (50) includes azimuth and elevation motors (64)(68) that are mechanically linked to the light (72), and a light power controller (70) that applies power to the light. In a typical situation, a remote light/receiving unit (50) would be attached to each upper corner of a structure and each unit (50) would be connected to the utility power line.

Abstract: An emergency lighting system having a motor drive assembly (34) for the automatic lowering of a battery-powered emergency lamp (12), when normal power to a primary lighting system is lost, from a concealed position behind a ceiling (11), and returning the lamp (12) to its original position when normal power is restored. Included in the assembly (34) are gears including a motor driven gear (36) and a crank arm driving gear (38). The presence of a normal electric current to the primary lighting system powers the motor drive assembly (34) to return and maintain the emergency lighting system in its concealed position. Interruption of normal electric power automatically results in driving of the emergency power system from its concealed position to an extended position for use, as a result of crank driving gear (38) being rotated in a direction opposite that in which it is rotated for return of the emergency system to the normal concealed position.

Abstract: An apparatus for properly adjusting an attitude of optical axes of head lamps on a vehicle includes a motor driven actuator and a controlling section. The motor driven actuator additionally includes a voltage dividing circuit comprising two resistors and one of a plurality of contact positions in the controlling section is earthed directly, whereby a resistance value of the controlling section becomes zero ohm when the angle of elevation assumed by the head lamps is maximized in an upward tilted state. A motor circuit in the motor driven actuator includes in a power supply line an element for preventing an excessive intensity of electric current from being fed to a motor when motor is held in a blocked state for some reason. Preferably, the element has positive temperature characteristics which suppress generation of heat when rotation of the motor is blocked.

Abstract: A rotary type clock ornament lamp circuit structure, which comprises a turner having a transmission shaft to turn a positive pole distribution member and a negative pole distribution member to carry a plurality of sockets and lamp bulbs to rotate. By means of a ring-shaped positive pole and negative pole conductive members to respectively contact the positive pole distribution member and the transmission shaft of the turner, the positive and negative poles of the sockets are respectively connected with a power source to turn on the lamp bulbs during rotary motion.

Abstract: A beacon lamp comprising a base, a support member fixed in relation to the base and a reflector carrier rotatably mounted on said support member for rotation relative thereto about a first axis. A drive motor carrier is resiliently supported by said support member such that in a rest position the principal axis of the motor carrier is disposed at a small angle to said first axis. An electric motor is supported by said drive motor carrier, and has its output member engaging a cylindrical wall of said reflector carrier, said motor carrier being deflected during positioning of said motor such that said principal axis is rendered substantially parallel with said first axis and said carrier resiliently biases the motor output member against said cylindrical wall of said reflector carrier.

Abstract: A retractable lamp assembly that is combined with the front end of a vehicle and includes a pair of lamps which can be alternately located within a headlamp opening in the front end of the vehicle so as to selectively project a beam of high intensity light or a beam of low intensity light forwardly of the vehicle.

Abstract: A motion-controlled light for movement about two independent axes is disclosed. The light includes a housing assembling having adjustably connected thereto a light assembly incorporating a high intensity arc lamp. The housing assembly is connected to a support assembly which provides for pivotal mounting of the housing assembly about the two axes. Separate fans are provided to cool the anode and the cathode of the arc lamp, providing a greater efficiency and longer life to the arc lamp.

Abstract: A light projector, suitable for entertainment lighting and comprising a light source and associated light collecting means producing an elongated beam having an optical centerline that is preferably substantially horizontal, is provided with a means, typically a mirror, mounted to a first support adapted for rotation about an axis coincident with that centerline, for redirecting the beam through a first plane perpendicular to that substantially horizontal axis and centerline. A second mirror is rotatably mounted to the first support so that the redirected beam falls upon it, redirecting the beam a second time, through a second plane perpendicular to the centerline of the beam in the region between the first and second mirrors; a second plane that is also substantially parallel to the axis of rotation of the first support. The first support is supported for rotation about said axis on both sides of the means for redirecting.

Abstract: Apparatus is described for a searchlight in which a lamp is mounted in a housing for both vertical and horizontal movement. Vertical drive means which is mounted in the housing includes a gear having a tooth portion and a ramp portion to permit up and down movement of said lamp. The housing has an integrally formed ring gear with a tooth portion less than 360 degrees and a ramp portion. A horizontal drive means engages the ring gear and drives the lamp in a horizontal plane less than 360 degrees.

Abstract: A lamp includes a bulb that is held within an openable housing. When the lamp is turned on, the bulb gradually lights and the housing gradually opens to expose the bulb. When the lamp is turned off, the housing closes around and thereby conceals the bulb. Methods for opening the housing include a sliding piston system, a cam and lifter system and a gear and rack system. When the lamp is turned on or off, music may also be played or other such sounds generated.

Abstract: A remote controlled spotlight system having a pair of spotlights on the ends of a horizontal shaft extending through a housing. A vertical shaft extends out of the housing for mounting purposes. An electric motor in the housing rotates the horizontal shaft about its longitudinal axis to aim the spotlights up or down. A second electric motor in the housing rotates the housing about the longitudinal axis of the vertical shaft to aim the spotlights left or right. The electrical motors are remotely controlled. An electrical power cord extends through the bore of the horizontal shaft, out through a hole in the horizontal shaft, and winds around the horizontal shaft at least twice. The cord then winds around the vertical shaft at least twice, and then passes through the bore of the vertical shaft to a power source.

Abstract: An actuator for a concealed headlamp has a linkage and support assembly including an intermediate carrier bracket and a pair of connecting links that allow the headlamp housing to be effectively rotated about a pivot axis located outside of the limited volume available for the actuator.

Abstract: Improvements are disclosed to systems adapted for the control of automated or variable parameter lighting fixtures and devices capable of varying a plurality of beam parameters such as the pan, tilt, size, shape, color, and focus on the basis of desired adjustments stored by the control system for each of a plurality of desired lighting effects. Such a control system is provided with a means, such as a port, for coupling to an external device having at least one output and capable of a plurality of conditions each of which may be used to identify a different lighting effect so that the operation of the control system and the external device may be synchronized.

Abstract: An improved apparatus for adjusting the azimuth and elevation of a light projector suitable for entertainment lighting, comprising a light source with associated light collecting and beam forming means producing an elongated beam having an optical centerline is disclosed. A means, typically a mirror, is used to redirect the beam at substantially right angles to the optical centerline, and is rotated to vary beam azimuth through a first plane. Both the light source and the means for redirecting are coupled to a common mechanical support, which is rotated around an effective pivot point perpendicular to the optical centerline and parallel to first plane, to vary beam elevation through a second plane at substantially right angles to the first plane. The unique advantages of the apparatus for remotely-adjusting fixtures and for systems mounting a plurality of lighting fixtures to a common mechanical support are disclosed.

Abstract: An adjustment bracket assembly is provided for attachment between an automotive vehicle frame member or the like and a headlamp housing or the like to permit pivotal motion of the headlamp housing relative to the frame member and about generally vertical and horizontal axes so as to achieve corresponding vertical and horizontal aiming of an associated headlamp beam. The adjustment bracket assembly comprises a one-piece integrally formed vertically elongate housing and support member defining generally vertically oriented, elongate guide bores for receiving and supporting an elongate drive shaft member with a free end thereof projecting outwardly of the housing and support member for engagement with a driver for operatively engaging the same with the headlamp housing for selectively causing pivotal movement thereof about one of generally vertical and horizontal axes to achieve one of vertical and horizontal aiming of the associated headlamp beam.

Abstract: The illumination system has primary and secondary light sources with a lamp current sensor control circuit for automatically switching from the primary lamp to the secondary lamp in the event the primary lamp fails. An illumination directing mirror is positioned between the light sources and directs one or the other of the light sources towards a fiber optic cable. The lamps are mounted on a movable carriage which is remotely controllable by a pneumatic cylinder. The carriage moves to alter the distance from the lamp to the port of the fiber optic cable. This controls the intensity of illumination entering the cable without changing the color temperature of the light.

Abstract: A headlamp assembly having a spring plate member fastened through a pivot connection to the lamp body and formed with a pair of clip members and a pair of spring members for allowing the lamp body to be readily secured to a support panel of a motor vehicle and allow selective adjustment of the lamp body about a horizontal aim axis and a vertical aim axis.

Abstract: A light for providing a larger diameter lighting pattern is comprised of a rotatable support. A motor for rotating the support at a frequency greater than the retention time of the human eye is provided. A source of light which provides a small lighting pattern is carried by the rotatable support such that upon rotation thereof a large diameter lighting pattern is created.

Abstract: An airport beacon light for producing a bright, color coded signal as a visual aid for airplane pilots. The light includes a metal halide lamp, a housing having a primary color coding lens, a lamp holder for accurately holding the lamp within the housing adjacent the lens, a color correcting auxiliary lens mounted adjacent the primary color coding lens for correcting the color of the light produced by the lamp through the primary lens.

Abstract: A device for adjusting the position of the headlamps of a vehicle both in azimuth and in elevation, the headlamp having a swivel joint at one end by which it is adapted to be mounted to the bodywork of the vehicle. The headlamp is connected to a mobile element by two pins at the other end of the headlamp, one of the pins lying on the horizontal axis of the headlamp and the other being offset with respect to the horizontal axis. The mobile element is mounted to slide horizontally on a support member fixed on the bodywork, and there is provided an adjusting device between the support member and the mobile element for adjusting the mobile element in azimuth. There is also provided a device for adjusting the mobile element in elevation, and this device is selectively adjustable either manually or by a drive member, this device for adjusting the mobile element in elevation acting on the pin that is offset with respect to the horizontal axis to drive the headlamp about the horizontal axis.

Abstract: An optical system directs the output beam of a light source along a first axis fixed relative to a first support carrying the light source. A second support mounted on the first support is rotated by a first motor about the first axis. A first reflector on the second support is oblique to and always intersected by the first axis. A third support mounted on the second support is rotated by a second motor about a second axis coincident with the reflection of the first axis in the first reflector. A second reflector on the third support is oblique to and always intersected by the second axis. By appropriate energization of the motors the light beam can be reflected in any direction.

Abstract: An adjusting device for the optical axis of an automobile headlamp includes a switch for setting the inclination angle or optical axis of the headlamp, and a motor operating in association with control relays and a current supply regulator for adjusting the inclination accordingly. In the event of inclination angle overshoot, the device automatically returns the headlamp to the selected inclination.

Abstract: A radio-controlled TV or movie studio spotlight or general purpose illumination instrument; two joy sticks, one for the pan or tilt, the other one for the dim or iris adjustments and settings, respectively, are installed on a panel of a 4-channel radio transmitter accessible for manual actuation to provide the respective commands for a four-channel radio receiver and thereby for the remote control of the lighting equipment functions.

Abstract: An illumination system having a continuous fixed ceiling panel, at least one light source suspended by a telescoping arm from the panel and a split-core transformer formed by two electroinductive coils enclosed in permanent magnets through which a magnetic field is created for the sealed transfer of electrical energy through the panel to the light source. One magnet is disposed on opposite surfaces of the panel. Rollers or a pneumatic system may be disposed between each magnet and the surface of the panel on which the magnet is disposed for sliding the magnets over the surfaces of the panel while maintaining the transfer of electrical energy. Secondary lighting means may also be included.

Abstract: A wiper-mounted retractable head lamp assembly for a vehicle, which assembly comprises a lamp, a lamp housing receiving therein the lamp to move therewith, the lamp housing being pivotably connected to the vehicle body so that is projectable from and retractable into a given space formed in the vehicle body and a head lamp wiper assembly for wiping the face of the lamp proper. Substantially all parts of the head lamp wiper assembly are mounted to the lamp housing to move therewith so that the pivoting movement of the lamp housing relative to the vehicle body is carried out without being affected by the presence of the wiper assembly.

Abstract: A portable lighting apparatus having a lamp assembly attached to the top of an elongated mast, preferably formed of interconnectable relatively short sections. The lamp assembly includes at least one electric lamp affixed to a horizontal shaft for rotation about a horizontal axis. Associated with the horizontal shaft are a pair of gears, suitably a vertical rack and a pinion engaged therewith, the pinion being operatively attached to the horizontal shaft. A spring associated with the pinion tends to rotate the gear in a direction which biases the engaged rack downwardly. The lower end of the rack abuts a movable pushrod generally centrally located within the hollow mast and running the length thereof. The lower end of the mast is telescopically mounted on a mast support provided with a fixed vertical stoprod which abuts the lower end of the pushrod.

Abstract: A method and an arrangement are disclosed for regulating a path length defined by a pressure-responsive unit. Whenever a coarse positional adjustment has been made, a pause period is made to elapse before a fine adjustment (if any) is carried out. This arrangement does not, due to the pause period, require any accommodation or tuning to regulating stages having different decay behaviors.

Abstract: Apparatus for opening and closing a retractable head lamp which includes a hand operated switch for effecting lighting and unlighting of the head lamp and initiating opening and closing movements of the head lamp, motor for driving a retracting mechanism for opening and closing the head lamp and a detector for detecting a desired position (opened and/or closed) of the head lamp and for selectively stopping energization of the motor when the head lamp reaches a desired position. A control means is connected between the hand switch and the detecting means and is responsive to operation of the hand switch from a lighting position substantially instantaneously to an unlighting position to prevent energization of the motor, thereby preventing closing of the previously opened head lamp.

Abstract: An apparatus containing a headlight gimballed for rotation within the enclosure of the apparatus. The headlight is capable of exposure through an opening in the enclosure, and is capable of directional adjustment in accordance with signals produced at a remote location. A cover is provided for selectively enclosing the opening which exposes the headlight, and is capable of selectively enclosing or exposing the opening in accordance with signals produced at a remote location.

Abstract: A kinematic lamp mount for mounting a spectral source lamp (3) such as a hollow cathode lamp accurately with respect to an optical axis of, for example an atomic absorption spectrophotometer comprises a base member (100), a lamp holder (1) and two spring means (120, 121) which urge the holder (1) into contact with the base member (100). The holder (1) is provided with three ball ended feet (6,8,10) two of which (6,8) are adjustable. Two feet (6 and 10) engage in an arcuate V-groove (102) while the third engages in a radial V-groove (103) giving kinematic connection between the holder (1) and base member (100).By providing kinematic connection between the holder (1) and base member (100) the lamp holder (1) and hence the lamp (3) may be removed from and later replaced sufficiently accurately on the base member (100) that no re-adjustment is necessary.

Abstract: A retractable headlamp assembly for automobiles in which a headlamp, pivotally mounted on the automobile frame, is operatively coupled to the rotatable shaft of a motor by a link mechanism. The motor, operating through the link mechanism, is energizable to cause the headlamp to be moved angularly between a first position at which the headlamp projects out of the front hood of the automobile, and a second position at which the headlamp is retracted within the front hood. An adjustable stop is provided to stop the headlamp at the first position, which adjustable stop is adjusted to bring the first position into conformity with an angularly displaced position of the rotatable motor shaft, which is displaced through a slip angle from a normal stopping position. Such an arrangement assures that the headlamp can be stopped at a fixed position at all times for emitting a correctly directed beam of light irrespective of the varying positions at which the motor can stop.

Abstract: A retractable head lamp structure for automobiles in which a head lamp assembly is mounted on the automobile body for pivotable movement about a pivot axis between an extended position and a retracted position. In the retracted position, the lens surface of the head lamp assembly is located along the body surface. The pivot axis is inclined downwardly and rearwardly with respect to a horizontal transverse line as seen in transverse outward direction of the body so that the lens surface is substantially flush with the body surface in the retracted position.

Abstract: An improved apparatus for illuminating a plurality of stairs when in use involves a transformer to provide a reduced A. C. voltage; at least one light in proximity to the stairs to illuminate the stairs when at least a portion of the reduced A. C. voltage is supplied to the light and an electrical circuit including the light is formed; a rectifier to convert the reduced A. C. voltage to a D. C. voltage; a plurality of pressure sensitive switches associated with the rectifier and the treads of the stairs; physical pressure on the tread or treads acting to close at least one of the switches; and a relay in association with the pressure sensitive switches and light, and adapted to form the electrical circuit including the light in response to the closing of at least one of the pressure sensitive switches.

Abstract: A mobile lighting unit which includes a plurality of lighting fixtures, each utilizing high-wattage, high-intensity lamps. The fixtures comprise a socket and hemispherical reflector assembly which are vertically and horizontally adjustably mounted to a lighting rack by an adjustable elbow member. The lamps are positioned in said fixtures so that their longitudinal axis is parallel to the light beam formed by the reflector, requiring one end of the lamp to be inserted in the socket and the other end to extend to the center of the hemispherical reflector. The lamps are cooled by pressurized air produced by a fan and transported through air tight channels in the lighting rack. The lamps are shock-dampened by mounting their socket end to a metal spring located on the interior wall of the socket and by attaching wires to the front end of the lamp, which are in turn attached to metal springs on the interior surface of the reflector. Thus, the lamp is fully shock absorber protected.

Abstract: A concealable headlamp assembly and an actuator therefor that provides an increased force output for moving the headlamp assembly from the concealed position to the exposed position when opening movement of the headlamp assembly is resisted.

Abstract: A rigid assembly of hollow tubes is caused to rotate simultaneously about vertical and horizontal axes while illuminated from below by a stationary light source. Balls confined within the tubes travel within said tubes during the rotational motion.

Abstract: A search and warning light system is disclosed, in its preferred forms, as including a light assembly having first and second lamp assemblies. The light assembly is mounted about a vertical axis for rotation in either a clockwise or counterclockwise direction and the lamp assemblies are mounted to the light assembly about a horizontal axis for rotation in either an upward or downward direction. A control module located in a remote location provides appropriate electrical input to the motors controlling the rotation of the light assembly and the lamp assemblies, and to the lightbulbs included within the lamp assemblies. The motor for rotating the light assembly is located exteriorly of the light assembly in a first embodiment and is located interiorly of the light assembly in a second embodiment. The lamp assemblies can be independently rotated by providing separate motors and drive mechanisms or can be rotated together by rotatably relating the lamp assemblies.

Abstract: A drive mechanism for revolving the turret of a searchlight assembly. The turret is rotated in an oscillating manner over an arc of less than 360.degree.. It is particularly characterized by smooth reversal allowing the driving of a high inertia turret without rapid motor overload and failure as characterized by other prior art methods of driving such mechanisms. A partial cylindrical track is concentrically disposed about the axis of rotation and attached to the turret. In the preferred embodiment, a link chain is welded along the bottom of the track, being folded back on the ends in a tear-drop shape. A drive sprocket on a swing arm is held into engagement with the chain and driven by a constant speed motor. The sprocket alternately drives along the inside of the chain and the outside of the chain smoothly traversing between the positions around the tear-drop ends to cause a smooth deceleration and acceleration.

Abstract: A lamp assembly includes a housing, a lamp bulb carrier slidably mounted in the housing for reciprocating movement along the optical axis of the lamp bulb and an actuator mounted in the housing for annular movement about an axis substantially perpendicular to the optical axis of the lamp bulb. The actuator has an eccentric portion engaging the lamp bulb carrier to effect reciprocation of the lamp bulb carrier when the actuator is angularly moved, and a switch carried by the housing is connected to the lamp bulb and connectable to an electrical power supply. The actuator also has a cam which engages and actuates the switch over a predetermined range of annular movement of the actuator to cause the lamp to be illuminated while the lamp is reciprocated along its optical axis.

Abstract: This specification discloses a motor vehicle flashing lamp and headlamp fixture to be attached to a motor vehicle body. The fixture provides a pivotable mouunting so that the flashing lamp and the headlamp can be aligned with respect to each other as well as the automobile body while maintaining a simple and relatively secure mounting. The mounting of the flashing lamps and headlamps in a body aperture of the motor vehicle includes a headlamp braced by an upper swivel providing an upper swivel point for the headlamp relative to the flashing lamp. An outer lateral lower adjusting device, movable forward and backward for the illumination range adjustment, is attached through a bracket to the flashing lamp or the body. An inner lateral upper adjusting device, which is movable forward and backward for the illumination direction adjustment, is attached to the body.

Abstract: An adjustable recessed electrical lighting fixture utilizing an electrical socket which engages a lamp. A mounting plate surrounds at least a portion of the lamp. A frame having a pair of legs pivotally connects the mounting plate and provides support for the electrical socket. The frame is pivoted in relation to the mounting plate to provide adjustment about a horizontal axis. A race which contacts at least a portion of the mounting plate is movable in relation to the mounting plate to provide adjustment about a vertical axis.

Abstract: A lighting device which is well adapted for inviting public attention by a conspicuous and decorative display of bright lights, is disclosed. The device includes at least one light source which is moveably mounted to a base. A motor and drive mechanism including a bent shaft is operatively associated with the light sources to orbit each light source around a respective center point. In many embodiments of the invention the drive mechanism is also adapted for continuously varying the angular positioning of each light source and of the emitted rays of light relative to the vertical direction.

Abstract: An apparatus for controlling angular position of optical axis of a head lamp assembly for a motor vehicle. An actuator is supplied selectively with the atmospheric pressure and a negative pressure available from an intake conduit of an internal combustion engine thereby to produce corresponding mechanical displacements. A detector for detecting the angular position of the optical axis of the head lamp assembly responds to the mechanical displacements of the actuator to change-over successively the contact states of a plurality of paired electric contacts. A command unit for setting the angular position of the optical axis of the head lamp assembly is provided which includes a plurality of paired electric contacts connected in one-to-one correspondence to the paired contacts of the optical axis position detector. A signal for setting the optical axis of the head lamp assembly is produced in dependence on the contact states of the optical axis position detector.

Abstract: Apparatus for adjusting the inclination of vehicular headlights includes a push rod assembly coupled to a headlight and to a position adjusting motor. The push rod assembly includes an articulated coupling to a motor driven actuating device to that coasting of the motor after deenergization does not alter the position of the headlight.

Abstract: In a beam-rotary lamp which has a reflector revolving around an electric lamp, an improvement is presented herein which is characterized by that a lamp unit is set together with a power unit comprising a reflector driving motor inside a closed helmet-shaped space, wherein the space is formed with a transparent bowl-shaped globe and an egg-shaped flat chassis put on said globe.

Abstract: A rotating lamp fixture including a spherical shell member rotatably supported on a vertically extending support member, a platform disposed in the shell member, a drive motor mounted on the platform, a stationary gear secured to a vertical support member, the shell member being rotatably mounted on the support member, the motor being drivingly connected to the stationary gear and being effective when energized to rotate the platform and the shell in which it is supported about the vertical support member, and a light bulb socket suspended within the shell member.

Abstract: An emergency warning lamp comprising a base, a mounting plate mounted on the base, and an electric motor mounted on the plate having an output shaft extending upwardly through the plate. A bushing is disposed centrally of the base on the plate, and a plastic gear is rotatably mounted on the bushing. A pinion meshes with the gear and is fixed to the shaft of the motor. A lamp bulb is mounted on the bushing. A heat shield overlies the gears and is supported by one of the gears for rotation. A reflector is mounted on the heat shield for rotation therewith. Electrical leads extend from a source of power, one of the leads comprising a ground lead and the others comprising power leads. One of the power leads extends through the bushing to the lamp. The other of the power leads extends to the winding of the motor. The housing of the motor is grounded to the metal plate and the ground lead is connected to the metal plate. The current flows through the bulb to the bushing and in turn to the mounting plate.

Abstract: The device comprises a bar pivoted to a swing-bar whose ends are each connected to a piston rod of a jack having two positions. The travel of one of the jacks is equal to double the travel of the other. The front end of the bar is connected to the upper part of a headlamp and the bar is connected to the middle of the swing-bar. The ends of the latter are formed over and engaged in notches formed in a support of the device. The edges of the notches constitute abutments for the swing-bar.