Radar Antenna Support And Drive Assembly

Abstract

Disclosed is an assembly including a horizontally extending radar antenna and feed horn mounting frame secured to side edges of a rotary upper pedestal part supported and driven by a combined bull gear and ball bearing mounted on a fixed pedestal part and removable via the top of the assembly without disturbing such mounting frame or the antenna and feed horn mounted thereon. Two drive assemblies each including bearings, shafts, and pinion gears engaging the bull gear at diametrically opposite locations and normally driven simultaneously by separate motor means via respective clutch means, are so mounted on the fixed pedestal part as to permit removal and replacement of either one while rotation of the assembly is maintained by the other. Normally retracted stud bolts are effectuable for providing rotary locking temporary support of the upper pedestal part by the lower pedestal part during a removal and replacement of the combined bull gear and ball bearing.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention

Radar antenna drive and support assemblies.

2. Description of the Prior Art

To date, insofar as applicant is aware, prior art antenna drive and support assemblies such as employed for airport surveillance use mounted atop support towers, are difficult to repair. In order to replace worn driving rotary support and other moving parts of these assemblies, considerable disassembly often is required in order to gain access to the wornout parts, with consequent downtime periods of nonuse of the radar equipment involving days and occasionally even weeks. Since such downtime is extremely undesirable in view of the reliance placed on radar surveillance for controlling traffic flow at busy airports, serious consideration has been given to installation of standby antenna drive and support assemblies at certain high traffic density airports to insure against any radar surveillance shutdown due to malfunction of the existing assemblies at these airports. While such redundancy offers a solution to the problem, it is objectionable at least from a cost standpoint.

SUMMARY OF THE INVENTION

In accord with salient features of the present invention, all driving, rotary support, and other moving components of the assembly are replaceable without dismantling the antenna reflector and feed horn and while the assembly is in place atop a support tower.

A large diameter annular bull gear supported by an antifriction bearing assembly mounted in a fixed pedestal part serves to turn the mounting members on which the antenna reflector and feed horn are disposed. Such mounting members and antenna components thereon are so disposed as to not interfere with access to the bull gear and bearing for replacement via a removable central top member. A cylindrical shoulder in the fixed pedestal part aids in rapid alignment of the bull gear bearing assembly during any replacement installation.

The bull gear is normally driven by two diametrically opposite spur gear pinions, either of which alone is capable of effecting bull gear drive in event of failure or momentary replacement shutdown of the other. During normal operation when both pinions are driving, the torque load reactions imposed by such pinions on the bull gear are equal and opposite and cancel out any resultant imposition of torque load reaction on the bull gear. At the same time, wear on either pinion and on the bull gear teeth is reduced by virtue of the sharing of work load by the two pinions.

The two drive pinions form parts of replaceable drive assemblies removably mounted on a fixed lower pedestal part and each of which includes the respective pinion, its drive shaft, antifriction bearings, and a sleeve in which such bearings are mounted. Either such drive assembly may be removed and replaced while the other continues in driving operation of the bull gear and its antenna load. A drainable and refillable reservoir formed in the fixed lower pedestal part retains lubricating oil for surround of the bull gear and its bearing as well as the two drive pinions and their bearings.

Two alike separately operable drive motor means, normally operated simultaneously, are removably mounted at accessible locations on depending motor mount bracket portions of the fixed lower pedestal part and are operatively connected, respectively, to the shafts of the aforesaid replaceable drive assemblies by way of respective clutch means and self-aligning couplings. Opportunity is thus afforded for separate replacement of either drive motor means and/or either drive assembly while the bull gear drive is continued by the other drive assembly and its motor means.

Provision is made for draining and reintroducing the lubricating oil into the aforementioned reservoir during replacement of either drive assembly.

In addition, the depending motor mount brackets of the fixed lower pedestal part extend downwardly below radially extending shoulders on such part which serve to mount the assembly atop a support tower, and a central space between these motor mount brackets accommodates a data takeoff assembly and a rotary joint and slip ring assembly for transmission of energy to the antenna feed horn and auxiliary devices.

BRIEF DESCRIPTION OF THE DRAWINGS

The above-mentioned features of the invention are more fully set forth in conjunction with the following description of the preferred embodiment of the invention presented in conjunction with the accompanying drawings, wherein:

FIGS. 1 and 2 are side elevation and top views, respectively, showing in general outline the radar antenna support and drive apparatus of the present invention as mounted on the upper end of a support tower;

FIG. 3 is a cross-sectional elevation view taken along the line III--III in FIG. 2, showing details of the invention; and

FIG. 4 is an exploded cross-sectional elevation view showing certain main rotary support and drive components of the FIG. 3 assembly, as removable and insertable from the top of such assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIGS. 1 and 2 in the drawings, the radar antenna support and drive assembly comprises a horizontally extending frame 1 which carries the usual feed horn 2 at one end and radar reflector 3 at the opposite end. In accord with the usual practice constant rotation of the frame 1 about a vertical axis 4 at its center causes the radar beam defined by reflector 3 to repeatedly scan 360.degree. in azimuth for such purpose as aircraft surveillance.

In accord with the invention, the antenna feed horn and reflector mounting frame 1 is so constructed and so secured to a rotary upper pedestal part 5 in a manner which does not obstruct access to the top of such part, at least in the vicinity of a central circular cover member 6 removably secured to such part 5 by machine screws 7. A suitable construction for the frame 1 may be as illustrated in FIG. 2 which includes side members 8 spaced-apart sufficiently to enable their disposition at opposite sides of rotary pedestal part 5 in suitable attachment thereto, preferably by means which enables the attitude of such frame to be adjusted relative to axis 4 for determining the elevation angle of the radar beam.

Removable waveguide components 10 extending from the center of cover member 6 to the feed horn 2 provides for transmission of radar energy to and from such feed horn while presenting an insignificant degree of obstruction to accessibility of cover member 6.

Disposed immediately beneath the circular cover member 6 is a combined bull gear and a ball bearing assemblage 11, FIG. 3, which is mounted on a horizontal annular shoulder 12 formed in a lower fixed pedestal part 13 and which is located coaxially with rotary axis 4 by a cylindrical shoulder 14 also formed in pedestal part 13.

The assemblage 11 comprises an annular bull gear 16 having teeth in its outer periphery and constituting the outer race of an antifriction thrust-transmitting bearing including an annular inner race 17 and the ball bearings 18 in circumferential array between the two races. The inner race 17 fits around cylindrical shoulder 14, seats on annular shoulder 12 and is removably secured in place by capscrews 20 insertable and removable from the top when cover member 6 is absent from the assembly. Bull gear 16 finds rotary support from the ball bearings 18 and in turn supports the cover member 6 which has an annular shoulder 22 at its under side for precise positioning on such bull gear and is secured thereto by capscrews 23. The outer diameter of the circular cover member 6 is greater than the outer diameter of the bull gear 16 to permit removal and insertion of the bull gear and ball bearing assemblage 11 via a central opening 24 in upper pedestal part 5 which becomes open when such cover member is removed. Removal of capscrews 20 frees assemblage 11 from annular seat 12, and to assist in its removal handles (not shown) can be secured to bull gear 16 by several of the capscrews 23 removed from cover member 6 at the time screws 7 are removed to permit removal of cover member 6.

In normal operation of the assembly, turning of the bull gear 16 on the ball bearings 18 about axis 4 causes the cover member 6 to be turned via capscrews 23, which in turn causes turning of the rotary upper pedestal part 5 via screws 7, hence turning of the mounting frame 1 and carrying the antenna reflector 3 and feed horn 2 with it about such axis 4. During such rotation, the feed horn 2 is maintained in communication with transmitting and receiving means (not shown) via the waveguide components 10 and others (not shown) in addition to a rotary waveguide joint 26 disposed centrally within fixed pedestal part 13 which also accommodates data takeoff sensor and other auxiliary equipment (not shown).

Fixed pedestal part 13 includes an annular portion 29 which is encircled by a downwardly extending skirt portion 30 of rotary pedestal part 5, which skirt portion includes an outwardly extending flange 31 at its lower edge. At a number of circumferential locations at the bottom of annular portion 29 of fixed pedestal part 13 mounting brackets 32 FIG. 2, provide for support of such part, hence the entire assembly, at suitable horizontal locations at the top of a mounting tower 35, indicated in dot-dash outline in FIGS. 1 and 2. At the same locations, and affiliated with such mounting brackets 32 stud bolts 34, one of which is shown in FIG. 3, are provided for support and antiturn or tilt securement of rotary pedestal part 5 and mounting frame 1 including reflector 3 and feed horn 2 thereon, during the time that cover member 6 is removed from such part 5 for inspection and/or replacement of the bull gear and bearing assemblage 11. Normally, each stud bolt is screwed deeply into the bracket to keep its projecting stud portion disposed below the flange 31 of rotary pedestal part 5. When brought into effectuation, a nut 36 stored on the end of the retracted stud bolt is removed to permit such bolt to be unscrewed upwardly from bracket 32 until its top threaded end passes through a respective opening 37 in flange 31 and an integral nut 39 of such bolt engages the underside of such flange for its support. The nut 36 is then again screwed onto the upper end of the bolt until it engages the top of flange 31 to protect pedestal part 5 and mounting frame 1 against tilt.

In accord with the invention, the bull gear 16 is normally driven simultaneously at diametrically opposite locations by a pair of pinions 40 rotated by matched pairs of electric motors 41, speed reducer mechanisms 42, a self-aligning assemblage 46 including universal joint couplings 43 and 44, and drive shafts 45; such coupling assemblage 46 being constructed and arranged for quick removal to provide freedom for removal of one or the other drive shaft 45 including its pinion 40. Each such removable pinion drive assembly includes, in addition to pinion 40 and shaft 45, ball bearing assemblies 50 and 51 on which such shaft rotates, and a sleeve 52 in which such bearing assemblies are mounted. Sleeves 52 fit slidably in downwardly opening bores 49 formed in the annular portion 29 of fixed pedestal part 13. Flanges 53 formed at the bottom end of such sleeves 52 provide for removable securement by caPscrews to such pedestal part at a readily accessible location. Each coupling assemblage 46 is made removable by providing long-length splines 47 on the drive shaft 45 which permits the lower coupling 43 to be slid free of short-length splines 48 on the output shaft 55 of the speed reducer 42. Thus either pinion drive assembly may be removed for replacement while the bull gear continues to be driven by the remaining pinion drive assembly until such replacement has been completed.

The electric motors 41 and speed reducer mechanisms 42 are removably, secured such as by bolts to respective depending bracket portions 57 of the fixed pedestal part 13, which portions extend downwardly from the mounting plane defined by the tower-top-mounted brackets 32 on such fixed pedestal part.

To provide for lubrication of all rotary components of the assembly, including the combined bull gear and ball bearing assemblage 11, pinions 40 in engagement with the bull gear 16, and the ball bearing assemblies 50 and 51 for the pinion drive shafts 45, the fixed pedestal part 13 is provided with an annular reservoir defined by inner and outer circular walls 60 and 61 coaxial with rotary axis 4 to retain lubricating oil 62; the top of bores 49 opening upwardly into the bottom of such annular oil reservoir. An oil plug 65 provides for draining the lubricating oil 62 from the reservoir via one of the other bore 49 and a respective port 66 prior to removal of one or the other pinion drive assembly, as well as for replacement of such oil upon replacement of such drive assembly.

While the invention has been described above in conjunction with a specific assembly, this has been by way of setting forth a preferred embodiment of the present invention as is not to be considered as limiting the scope of the invention except as set forth in the following claims.

Claims

I claim as my invention:

1. A radar antenna support and drive assembly comprising,

a fixed pedestal part adapted to be mounted atop an antenna tower,

a main-support rotary bearing removably mounted on the top of said fixed pedestal part,

a bull gear mounted on said main-support rotary bearing,

a rotary pedestal part having a removable top cover member removably secured to said bull gear,

a reflector and feed horn mounting frame secured to said rotary pedestal part and without obstruction to removal of said top cover member,

a pair of pinion drive assemblies removably secured to said fixed pedestal part, including pinions engaging diametrically opposite points on said bull gear, bearings, and drive shafts for such pinions,

motor means for such drive shafts removably mounted on said fixed pedestal part, and

normally ineffectual means for supporting and locking said rotary pedestal part against rotation and tilt during removal of said top cover member.

2. A radar antenna support and drive assembly comprising,

a circular fixed pedestal part having horizontally extending assembly mounting brackets for securement to tower top members, two oppositely arranged depending motor-drive mounting brackets extending downwardly from the plane of such assembly mounting brackets, an annular lubricating oil reservoir encircling a horizontal annular bearing seat coaxial with the center of such circular pedestal part through which a vertical axis of rotation for the aforesaid assembly passes, and a pair of vertically extending drive assembly accommodating bores opening upwardly into the bottom of such oil reservoir at circumferential locations embraced by such downwardly extending motor-drive mounting brackets and radially outward with respect thereto,

a main-support ball bearing assembly having an inner annular race seated on said annular bearing seat and removably secured in place by capscrews extending downwardly from the top of such race,

an annular bull gear rotatably supported by ball bearings of said main support ball bearing assembly and encircling said inner annular race within said oil reservoir,

a circular rotary pedestal part having a horizontally extending central top cover member mounted on said bull gear and secured thereto by top-removable capscrews and a downwardly extending skirt portion encircling the annular oil reservoir region of said fixed pedestal part and having an outwardly extending flange at the bottom thereof disposed above the plane of the assembly mounting brackets of said fixed pedestal part,

said central top cover member being secured to said skirt portion by top-removable screws and being of larger outer diameter than that of said bull gear to permit removal of such bull gear and of said main support ball bearing assembly upon removal of such cover member,

a horizontally extending antenna reflector and feed horn mounting frame secured to said skirt portion of said rotary pedestal part for support thereon and rotation therewith about said axis of rotation,

a pair of removable pinion drive assemblies including pinions disposed in said oil reservoir in driving engagement with said bull gear at diametrically opposite locations, rotary pinion drive shafts secured to said pinions, antifriction bearing for such shafts, and sleeves in which such bearings are mounted,

said sleeves being removably mounted in the aforesaid drive assembly accommodating bores of said fixed pedestal part and secured in place by bottom removable means,

a pair of drive motor means removably mounted on said motor-drive mounting brackets, respectively,

disengageable coupling means rotarily connecting said pinion drive shafts to the outputs of said drive motor means, respectively, and

normally retracted stud bolt means on said assembly mounting brackets screwable upwardly into supporting engagement with the underside of the flange on the skirt portion of said rotary pedestal part and into projection through openings in such flange for locking such part against rotation and tilt during removal of its top cover member.

3. The assembly of claim 2, including wave guide means extending centrally upward between said motor-drive mounting brackets and said top cover member and laterally therefrom for connection to the feed horn on said mounting frame,

said wave guide means including a removable section permissive of removal of said top cover member without disturbing such feed horn.