Fixture lowering assembly

A fixture lowering assembly for lowering fixtures, such as security and surveillance cameras, that require connection and disconnection of multiple complex electrical contacts is disclosed. The assembly includes a fixed housing that is mounted above ground level and a movable housing containing the fixture and being capable of being lowered to the ground level. A connect unit connects the fixed and movable housings and includes a latching assembly and first and second electrical connectors. The first and second connectors are each mounted on a pair of guide rods that extend through a pair of springs so that the first and second connectors freely float to facilitate connection and disconnection. The electrical connectors also include mounting bodies capable of receiving a variety of different electrical contact plates depending upon the type of fixture used with the lowering assembly. This construction of the contact plates also provides a moisture proof seal about the pins and sockets. The electrical contact plates include pin and socket electrical contacts and the pins are mounted on one of the plates in recesses below the outer surface of the plate in order to protect the pins from inadvertent damage. The opposite plate includes projections that engage the recesses in the opposite plate in order to ensure correct alignment between the pins and sockets. The electrical contact plates and the mounting posts for the first and second connectors may also include, respectively, leading alignment members and leading alignment posts to further facilitate correct alignment of the electrical contacts.

BACKGROUND OF THE INVENTION
 This invention generally relates to assemblies for lowering an electrical
 fixture from elevated locations and more particularly to a fixture
 lowering assembly adapted for lowering suspended fixtures, such as
 security and surveillance cameras, that require connection and
 disconnection of multiple complex electrical contacts.
 Fixture lowering assemblies for devices such as mast-supported street
 lights or other lighting devices positioned at a high elevation are well
 known. U.S. Pat. No. 5,393,245 discloses such a lowering assembly for
 lowering a light fixture for servicing. The device includes a standard
 three-prong electrical plug that must be connected and disconnected when
 lowering the light fixture.
 Many of such prior art devices are not suitable for providing a connection
 for more complicated electrical fixtures, such as cameras, video recorders
 and the like. This is because such complex electrical devices require many
 more electrical contacts for providing power to the device and permitting
 transmission of signals from the device, such as a camera, back to a
 receiving or viewing station. The complexity of the electrical connection
 can hinder the disconnecting or connecting process and can also cause
 damage to the fixture if there is ununiform disconnection or connection of
 only some of the electrical contacts.
 U.S. Pat. No. 5,718,602 discloses a suspension connector assembly designed
 for use with more complex electrical devices such as cameras that require
 multiple pin and barrel-type socket electrical connectors. However, the
 pins 55 of the electrical connection project outwardly from a rubber base
 7 with no mechanism provided on the base 7 for guiding the pins 55 into
 the sockets on the other half of the connector. The pins 55 may therefore
 encounter difficulty in finding the corresponding sockets and could
 potentially be damaged during attempted insertion into the sockets. The
 base 7 of the pins 55 is also rigidly fixed and therefore cannot
 compensate for any variation in the connection process. This rigid
 fixation of the pins, while an upward force is being applied, further
 enhances the possibly of misalignment, bad connection, or damage to the
 pins 55.
 SUMMARY OF THE INVENTION
 One object of the present invention is to provide an improved fixture
 lowering assembly for use with, for example, security or surveillance
 cameras that have multiple contact positions required to form an adequate
 electrical connection. For example, in an embodiment, the fixture lowering
 assembly can provide up to twenty-nine contact positions for use with a
 variety of different security and surveillance cameras for disconnecting
 and connecting the power and signal wires so that the camera may be
 lowered for maintenance. However, it will be understood that the fixture
 lowering assembly of the present invention can be used with a variety of
 electrical fixtures requiring varying types of electrical connections.
 The fixture lowering assembly of the present invention provides an improved
 electrical connection by providing first and second connectors, each
 respectively provided with pins and sockets, that both have a biased
 mounting that permits both the first and second connector to float. The
 first and second connectors are preferably mounted on respective sets of
 upper and lower guide posts with springs mounted therein for providing a
 floating effect to the first and second connector. By providing a spring
 mounting and permitting both the first and second connectors to float, the
 first and second connectors can adequately compensate for variations in
 alignment and force during the connection process in order to facilitate
 an effective connection between the pins and the sockets.
 The fixture lowering assembly of the present invention is also designed to
 protect the pins provided on the connector during the connection process.
 This is accomplished by providing on the ends of the guide posts that hold
 the first and second connectors with a respective set of alignment posts
 and receptacles that cooperate to engage and align the first connector
 with the second connector. The alignment posts and receptacles preferably
 come into contact before the pins and sockets in order to ensure a proper
 alignment.
 To further facilitate accurate correction, the contact pins are provided in
 a recess or recess on the connector so if the pins are in a protective
 environment in order to prevent an pertinent damage, such as bending of
 the pins. The opposite connector includes projections (which house the
 electrical sockets) that fit into the recess on the other connector prior
 to engagement of the pins with the sockets to further ensure proper
 alignment with the pins and the sockets.
 Another object of the present invention is to provide an improved fixture
 lowering assembly that can be used with a variety of electrical
 connections, such as for security and surveillance cameras, video cameras,
 etc. This is accomplished by providing the first and second connectors
 with mounting bodies that are capable of receiving a variety of electrical
 contact plates. The electrical contact plates can be selected for the
 particular intended fixture and easily placed within the mounting bodies
 of the first and second connectors.
 In an embodiment, the fixture lowering assembly of the present invention
 comprises a fixed housing mounted above ground level and a movable fixture
 housing connected to a fixture. A connect unit is used to secure the fixed
 housing to the movable housing and includes an upper portion mounted on
 the fixed housing and the lower portion mounted on the movable housing. A
 latching assembly is provided on the upper and lower halves of the connect
 unit for permitting selective connection and disconnection of the two
 halves of the connect unit as well as the fixed and movable housings.
 The upper portion of the connect unit includes a first electrical connector
 and the lower portion of the connect unit and includes a second electrical
 connector. A first spring assembly resiliently mounts the first connector
 on the upper portion of the connect unit and a second spring assembly
 resiliently mounts the second connector on the lower portion of the
 connect unit. The first and second connector each include electrical
 contacts for forming the electrical connection required for the fixture.
 The first and second connectors are preferably comprised on a mounting body
 and a selected electrical contact plate provided in the mounting body. The
 electrical contact plates can be easily removed from the mounting bodies
 and replaced in order to adapt to the circuitry required for a variety of
 different features. In order to accommodate a wide variety of fixtures,
 the mounting bodies preferably include up to 29 positions for receiving
 electrical contacts.
 In most instances, the electrical contact plates can be provided with
 electrical contacts in the form of a plurality of pins and barrel-type
 sockets. One of the electrical contact plates preferably includes an outer
 surface and recesses with electrical contact pins being provided in the
 recesses and not projecting outwardly beyond the outer surface of the
 electrical contact plate. This construction prevents inadvertent damage to
 the pins since they are shielded by the recesses.
 The opposite electrical contact plate includes a plurality of projections,
 each including an electrical socket, for receipt in the corresponding
 recess in the other electrical contact plate. In an embodiment, one of the
 electrical contact plates includes a box recess, a plurality of
 cylindrical recesses, and a plurality of pins provided in the box recess
 and in the cylindrical recesses. The other electrical contact plate is
 then provided with a corresponding box projection, a plurality of post
 projections and a plurality of electrical sockets provided in the box and
 post projections.
 The fixture lowering assembly also includes other components for aligning
 the first and second electrical connectors. In an embodiment, first and
 second spring assemblies resiliently mount the first and second connectors
 and each include a pair of guide posts extending through a pair of springs
 to mount the respective connector. Alignment posts extend outwardly from
 one set of guideposts and corresponding receptacles are provided on the
 other set of guide posts. The alignment posts come into contact with
 receptacles in the opposite guide posts prior to any contact between the
 first and second connectors in order to create a correct alignment between
 the components before the electrical connectors themselves are brought
 into contact.
 The electrical contact plates of the first and second connectors can also
 include leading alignment members on one of the plates and corresponding
 receptacles on the other plate to further ensure correct alignment between
 the respective components. The combination of the alignment posts and
 receptacles on the guide posts, the alignment members and receptacles on
 the electrical contact plates, and the recesses and projections on the
 plates ensure correct alignment and insertion of the pins into the
 electrical sockets.

DESCRIPTION OF THE PREFERRED EMBODIMENTS
 Referring to FIGS. 1 to 3, the numeral 10 generally designates the fixture
 lowering assembly of the present invention. The assembly 10 includes a
 fixed upper housing 11 which is mounted above ground level and is shown
 mounted at the top of a pole 13. While a pole mounting is shown, it will
 be understood by those skilled in the art that the mounting for upper
 housing 11 and the location and height of the elevation may vary
 considerably depending upon the application for which the fixture lowering
 assembly is intended.
 The assembly 10 also includes a movable housing 12 which includes a fixture
 14. The fixture 14, in the embodiment shown in the drawings, comprises a
 security and surveillance camera mounted within a backing 14a and a clear
 dome 14b for overhead viewing above ground level. Typically, such cameras
 require a plurality of electrical contacts in order to provide power to
 the fixture 14 and to relay a signal from the fixture back to a receiver
 or viewing system. Such cameras may require up to twenty-nine contact
 positions. While the invention will be generally described in connection
 with using a security and surveillance camera for fixture 14, it will be
 understood by those skilled in the art that the present invention may be
 used with a variety of electrical fixtures 14.
 The fixture 14 is lowered on a cable 15 designed to withstand harsh weather
 conditions including gusting winds. In an embodiment, the lowering cable
 15 comprises a 5/32 inch thick stainless steel aircraft cable. The cable
 15 is used for lowering fixture 14 for a variety of purposes such as
 servicing by personnel 16, installation of a new camera or other fixture,
 changing film or lenses, etc. A standard winch system (not shown) may be
 used for lowering cable 15. The winch system need not be described herein
 in detail since such systems are well-known to those skilled in the art.
 In order to connect and disconnect the upper fixed housing 11 and lower
 movable housing 12 of the lowering assembly 10, a connect unit generally
 designated at 17 is provided between these two components. The connect
 unit 17 has a top half 17a and a bottom half 17b which may be formed of
 cast stainless steel or similar suitable materials. The connect unit 17
 generally includes two main assemblies: (1) a latching assembly generally
 designated at 18 for connecting and disconnecting the two halves 17a and
 17b; and (2) a contact assembly generally designated at 19 for connecting
 and disconnecting the electrical contacts between the two components.
 The latching assembly 18 is well-known to those skilled in the art and is
 used in suspension connectors manufactured by Lighting and Lowering
 Systems, Broadview, Ill., the assignee of this application. For example,
 the latching mechanism has been employed in product model No. SCU-2A. The
 latching assembly 18 will therefore only be described in general detail.
 Referring to FIG. 4, the latching assembly 18 generally includes an
 elongated post on one half 17b of the unit 17 that fits into a socket 21
 on the other half 17a of the connect unit 17. The post 20 is provided with
 guide member 22 and socket 21 includes a respective slot (not shown) for
 receiving such guide member 22. The lower half 17b of the connect unit 17
 further includes a guide sleeve 23 for receiving an elongated guide member
 24. These features ensure a proper alignment of the two halves 17a and 17b
 and of the latching assembly.
 The top half 17a of the connect unit 17 defines a slotted channel 25 and a
 central hook member 26. The other half 17b of the connect unit 17 includes
 a pair of pivotally mounted latch arms 27, which each include pins 28 for
 passage in guide channel 25 and engaging hook 26. As is known by those
 skilled in the art, when the lower half 17b is pulled upward by cable 15
 to connect with the upper half 17a, the arms 27 pivot and pins 28 pass in
 the direction of arrow 29a through channel 25 and engage hook 26 to latch
 the two halves together. When it is desired to disconnect the two halves
 17a and 17b, the lower half 17b is again pulled upward on cable 15 so that
 the pins 28 on the latch arms 27 follow the path of arrow 29b to then
 unlatch the two members. As stated above, such a latching assembly is
 well-known to those skilled the art and need not be described in further
 detail herein.
 Referring to FIGS. 2 and 4, the contact assembly 19 for forming the
 electrical connection comprises a first connector 30 and a second
 connector 31. The top half 17a of the connect unit 17 is connected to a
 mounting plate 32 by a bolt or screw 33 and a pair of upper guide posts 34
 extend through mounting plate 32. The upper guide posts 34 support the
 first connector 30 for forming an electrical connection with the second
 connector 31.
 The bottom half 17b of the connect unit 17 is connected to a second
 mounting plate 35 by a bolt or screw 36 and a pair of lower guide posts 37
 pass through the mounting plate 35. The second connector 31 is supported
 by the mounting posts 37 for connection with the first connector 30.
 Referring to FIG. 5, the first and second connectors 30 and 31 and mounting
 assemblies are presented in exploded views that show the components in
 more detail. Screw 33 is used to connect mounting plate 32 to the upper
 half 17a of the connect unit 17, and screws 38 are used to secure upper
 guide posts 34 to mounting plate 32 by connecting with threaded bores 34a
 in posts 34. The upper guide posts 34, when assembled, extend though a
 pair of springs 39 to support the first connector 30. Specifically, the
 upper guide posts 34 pass through flange bearings 40 that are received in
 apertures 41 in first connector 30. A pair of upper alignment posts 42
 extend through a pair of retainers 43 and have threaded ends 42a extend
 through the first connector 30 and are secured into threaded recesses 34b
 of the upper guide posts 34. The upper alignment posts 42 and retainers 43
 secure the first connector 30 on the guide posts 34 but permit the first
 connector 30 to slide on flange bearings 40 along guide posts 34 against
 the biasing force of the spring 39.
 The lower guide posts 37 include threaded ends 37a that, when assembled,
 pass through the second connector 31 and a second pair of springs 44 and
 through mounting plate 35. The threaded ends 37a of the lower guide posts
 37 then pass through a pair of flange bearings 45 and are threadably
 connected to a pair of adjustment nuts 46. the nuts 46 can be turned on
 threads 37a to adjust the length of the lower guide posts 37 that projects
 through the mounting plate 35. The screws 47 secure the mounting plate 35
 to the bottom half of assembly 17b.
 An optional rubber gasket 48 can be provided between the first and second
 connectors 30 and 31 to facilitate the moisture proof seal between the two
 connectors.
 In the embodiment shown in the drawings, the first and second connectors 30
 and 31 each respectively include a mounting body 50 and 51 and a
 corresponding electrical contact plate 52 and 53. The mounting bodies 50
 and 51 are intended to be of a standard configuration that permit the
 electrical contacts, in the form of electrical contact plates 51 and 52,
 to be interchanged and selected depending upon the particular fixture used
 with the lowering assembly of this invention.
 In the embodiment shown in the drawings, mounting body 50 defines apertures
 41 the receive flanges 40 for permitting slidable movement on upper guide
 posts 34. The mounting body 50 also defines a receptacle 54 so that a
 selected electrical contact plate 52 may be inserted therein. The opposite
 side of mounting body 50 defines a plurality of pre-drilled apertures 55
 that have a thin membranes 56 separating the apertures 55 from the
 receptacle 54. The pre-drilled holes 55, and thin membranes 56, permit the
 holes to be selectively drilled through to correspond to the appropriate
 number of electrical contacts needed for the particular fixture used with
 the assembly. The thin membrane 56 protects the circuitry by sealing off
 unused apertures 55 whereas the thin membrane 56 can be easily removed
 depending upon the number of electrical contacts needed.
 The mounting body 51 is similar to mounting body 50 and includes apertures
 57 that encapsulate upper shank of lower guide posts 37. The mounting body
 51 also includes a receptacle 58 for receiving electrical contact plate
 53, as well as apertures 59 and thin membranes 60 for permitting selective
 connection of electrical contacts through body 51 to contact with the
 electrical contact plate 53.
 Typically, the type of fixture, such as a surveillance and security camera,
 used with the lowering assembly 10 of the present invention will use pin
 and socket connectors. In the embodiment shown in the drawings, electrical
 contact plate 52 is adapted for providing socket connectors and electrical
 contact plate 53 is adapted for providing pin connectors. However, it will
 be understood by those skilled in the art that the pin and socket
 connectors can be used with either the first or second connector 30, 31 or
 that other types of electrical contacts can be used to make the electrical
 connection depending upon the particular application for which the
 invention is intended.
 FIGS. 6 and 7 illustrate one type of electrical contact plate 52 for use
 with socket connectors and one type of electrical contact plate 53 for use
 with pin connectors. In particular, electrical contact plate 52 includes a
 base 61, a plurality of rod-like projections 62, and a block projection
 63. The rod-like projections 62 define apertures 62a and electrical
 sockets 64 are provided inside of projections 62 for receiving a pin.
 Similarly, block projection 63 defines a plurality of apertures 63a which
 each contain an electrical socket 64. The electrical sockets 64 are
 inserted through apertures 55 and thin membranes 56 in the mounting body
 50 in order to provide the desired number of electrical sockets 64
 depending upon the number of electrical contacts needed. In the embodiment
 shown in the drawings, the electrical contact plate 52 is adapted to
 provide up to twentynine electrical contacts which would advantageously
 accommodate most types of surveillance and security cameras.
 The electrical contact plate 53 includes circular recesses 65 corresponding
 to the rod-like projections 62 of contact plate 52 and a block recess 66
 corresponding to the block projection 63 of the contact plate 52. A
 plurality of pins 67 project upwardly through recesses 65 and block recess
 66 for mating with the corresponding apertures 62a and 63a in the opposite
 projections 62 and 63. As shown in FIG. 7, the electrical contact pins 67
 are inserted through the openings 59 and thin membranes 60 of the mounting
 body 51. In the embodiment shown in the drawings, the electrical mounting
 plate 53 is also capable of including up to twenty-nine different contact
 pins. However, the number of electrical contact pins 67, and sockets 64 on
 plate 52, can be selectively varied depending upon the electrical contacts
 needed for the fixture and depending upon the particular application for
 which the invention is intended.
 Referring to FIG. 5, the alignment posts 42 include projecting heads 42b
 that are adapted to fit in receptacles 37b defined by the opposite guide
 posts 37. The heads 42b contact the receptacles 37b during connection
 prior to any contact between the pins 67 and the sockets 64. Thus, the
 alignment posts 42 facilitate correct alignment of the pins 67 and sockets
 64 in order to prevent damage thereto or a misaligned connection.
 The particular configuration of electrical contact plates 52 and 53 also
 facilitates the correct alignment of the electrical contacts. The posts 62
 and cylindrical openings 65 help ensure proper alignment of the pins and
 sockets because the posts 62 and opening 65 engage in proper alignment
 prior to any contact between the actual pins and sockets. Likewise, the
 block projection 63 and the corresponding recess 66 align prior to contact
 between the pins 67 and socket 64 to ensure correct alignment. Notably,
 the pins 67 also do not project outwardly beyond the outer face 68 of the
 electrical contact plate 53 and are preferably recessed below the face 68
 to prevent damage to the pins during the disconnection and connection
 process.
 To further facilitate correct alignment of the components of the two
 electrical contact plates 52 and 53, contact plate 52 is provided with
 leading alignment members 69 that extend outwardly beyond posts 62 and
 block projection 63. The opposite contact plate 53 is provided with
 elongated receptacles 70 for receiving alignment members 69 during the
 connecting process. By front running actual contact between the electrical
 contact plates 52 and 53, the leading alignment members 69 and receptacles
 70 further bring the components into proper alignment to facilitate the
 connection between the electrical contacts. Pursuant to the embodiment
 given in the drawings, the leading alignment members 69 and corresponding
 receptacle 70 may advantageously have a generally rectangular
 cross-section and do not project outwardly too much from the entire
 assembly while still having a sufficient surface area engagement to help
 ensure proper alignment of the components.
 In addition to facilitating alignment, the employment of projections and
 recesses on the two electrical contact plates 52 and 53 further provides a
 moisture-proof seal about the contact points between the pins and sockets.
 The moisture-proof seal is very advantageous since a fixture lowering
 assembly is commonly used in outside environments subject to the elements.
 The first and second connectors 30 and 31 are each respectively mounted on
 their guide posts 34 and 37 and springs 39 and 44 to provide a "fully
 floating" connection. This fully floating assembly of the first and second
 connectors 30 and 31 facilitates correct alignment of the components
 because the connectors can adjust or "give" if needed during the alignment
 and connection process.
 During the operation of disconnecting or connecting the two halves 17a and
 17b of the connect unit 17, the springs 39 and 44 that respectively
 support the first and second connectors 30 and 31 compress in order to
 permit the lever arms 27 and pins 28 to engage and lock on hook 26 to
 connect the two components together. However, it should be noted that
 neither of the springs 39 or 44 is alone capable of sufficient compression
 to permit latching of the first and second halves 17a and 17b together.
 Rather, both springs 39 and 44 must cooperate to provide sufficient
 compression to permit latching of the two components 17a and 17b together.
 In an embodiment, the latching assembly 18 requires a stroke length of
 approximately 3/4 of an inch for pin 28 to be latched or unlatched from
 hook 26. In this embodiment, each of the spring mountings for the first
 and second connectors 30 and 31 provide approximately 3/8 of an inch
 movement to accommodate for the latching and unlatching stroke. However,
 it will be understood that the latching stroke length and the degree of
 movement of the first and second connectors 30 and 31 could be varied
 depending upon the particular application for which the fixture lowering
 assembly is intended.
 To insert the pins 67 into the sockets 64, a coupling force is required. In
 an embodiment, the coupling force is equal to thirty-two pounds of
 pressure. To overcome this force, the springs 39 and 44 combine to provide
 a force greater than the coupling force between the pins 67 and sockets
 64. In an embodiment, each of the springs 39 and 44 provide approximately
 sixteen pounds of pressure which, when the forces are combined, is
 sufficient to overcome the coupling force required between the pins 67 and
 sockets 64. However, it should be noted that the spring force provided by
 each of the individual springs 39 and 44 is each less than the total force
 required to overcome the coupling force required between the pins 67 and
 socket 64. However, it will be understood by those skilled in the art that
 the coupling force and the offset force provided by the springs will vary
 depending upon the particular application for which the socket lowering
 assembly is intended.
 During the connection and disconnection process, the fully floating design,
 provided by the springs 39 and 44 that resiliently mount the first and
 second connectors 30 and 31 permits each of the connectors 30 and 31 to
 follow each other throughout the connection and disconnection process. In
 other words, the first and second connectors 30 and 31 remain coupled
 throughout the latching and unlatching process and the spring mounting of
 each connector prevents a partial disconnection or connection which could
 cause damage to the fixture due to an imbalance in the connection of the
 electrical contacts. The spring mounts thus maintain the connection until
 the first and second connectors 30 and. 31 are fully extended on their
 respective guideposts 34 and 37 so that disconnection occurs evenly and
 uniformly to prevent inadvertent damage to the system.
 Although we have described our invention by reference to particular
 illustrative embodiments thereof, many changes and modifications of the
 invention may become apparent to those skilled in the art without
 departing from the spirit and scope of the invention. We therefore intend
 to include within the patent warranted hereon all such changes and
 modifications as may reasonably and properly be included within the scope
 of our contribution to the art.