Title:
UNDERSLUNG GATE SUSPENSION
United States Patent 3641942


Abstract:
Safety retaining structure is described that is applicable to a load dividing gate mounted on longitudinal rails by means of a special underslung suspension which provides clearance for an overhead central obstruction while retaining the known action of a squaring shaft. The suspension further includes vertical adjustment at each rail and permits swinging movement of the gate structure about an axis parallel to the squaring shaft.



Inventors:
Konrad, Marion G. (Hacienda Heights, CA)
Erickson, John W. (Huntington Beach, CA)
Application Number:
05/052334
Publication Date:
02/15/1972
Filing Date:
07/06/1970
Assignee:
PRECO INC.
Primary Class:
International Classes:
B61D45/00; (IPC1-7): B60P7/14
Field of Search:
105/376
View Patent Images:
US Patent References:
3570416FREIGHT-BRACING APPARATUS1971-03-16Shook
3549291RETAINING STRUCTURE FOR LOAD DIVIDING GATE SUSPENSION1970-12-22Pettigrew et al.
3464369SUSPENSION AND LOCKING MECHANISM FOR LOAD DIVIDING GATE1969-09-02Erickson et al.
3208403Load divider suspension1965-09-28Magarian et al.



Primary Examiner:
Hoffman, Drayton E.
Claims:
What is claimed is

1. In combination with a suspension for a load dividing gate structure, said suspension comprising a pair of fixedly mounted longitudinally extending and laterally spaced overhead rails having upwardly facing supporting surfaces and downwardly facing racklike formations, bracket structures mounted on the gate structure and extending upwardly therefrom adjacent the respective rails, gate supporting rollers journaled on the respective bracket structures and riding the support surfaces of the respective rails, a squaring shaft journaled on the bracket structures in spaced relation below the rollers and parallel to the axes thereof, and sprocket wheels rotatively fixed at the respective ends of the shaft and engaging from below the racklike formations of the respective rails to normally maintain the squaring shaft in uniform angular relation to the rails, at least one roller and the corresponding sprocket wheel being axially movable relative to the bracket structure and to the squaring shaft, respectively, to accommodate slight variations in spacing between the rails; safety retaining structure comprising

2. In a suspension for a load dividing gate structure, said suspension comprising a pair of fixedly mounted longitudinally extending and laterally spaced overhead rails having upwardly facing supporting surfaces and downwardly facing racklike formations, bracket structures mounted on the gate structure and extending upwardly therefrom adjacent the respective rails, gate supporting rollers journaled on the respective bracket structures and riding the support surfaces of the respective rails, a squaring shaft journaled on the bracket structures in spaced relation below the rollers and parallel to the axes thereof, and sprocket wheels rotatively fixed at the respective ends of the shaft and engaging from below the racklike formations of the respective rails to normally maintain the squaring shaft in uniform angular relation to the rails; improved structure for mounting said bracket structures on the gate structure, comprising

3. The improvement defined in claim 2, and in which said journaling means comprise

4. The improvement defined in claim 2, and in which

5. The improvement defined in claim 4, and including also

Description:
This invention has to do generally with improved suspension mechanisms by which load dividing gates may be supported and moved between selected working positions in the vehicle lading compartment of a transport vehicle.

An important object of the present invention is to provide improved suspension mechanisms for use in presence of overhead obstructions such as ventilating ducts, for example, which commonly extend along the center of the lading compartment ceiling.

It is common practice to suspend load dividing gates by suitable rollers from two parallel rails that extend longitudinally of the lading compartment. Such rails are ordinarily mounted near the vehicle ceiling to avoid interfering with the lading. That desirable rail location is made possible even in presence of central overhead obstructions by use of suspension structures of the general type described and claimed in U.S. Pat. No. 3,208,403, issued on Sept. 28, 1965 to Gerald M. Magarian and Paul Z. Anderson and assigned to the same assignee as the present application. In those structures the suspending rollers are journaled on brackets that extend upward from the gate close to the respective rails. The gate structure is maintained at right angles to the rails by a squaring shaft journaled on those brackets below the rails and carrying sprocket wheels that engage the lower rail surfaces. The sprocket teeth thus enter defining formations on the rails from below. In such an underslung suspension the squaring shaft is low enough to clear most overhead obstructions, while permitting the rails to be mounted close to the car ceiling.

A more particular object of the present invention is to facilitate installation of suspension structures of the described type by providing mechanism by which the height of the suspended gate can be adjusted independently with respect to each of the supporting rails, thereby varying the lateral position of the bottom edge of the gate.

A further object of the invention is to provide underslung suspensions that are more reliable and safe in operation.

The present invention is useful both for gate structures in which the gate proper is confined to a plane parallel to the squaring shaft and to gate structures that include a beam parallel to the squaring shaft with a carriage movable along the beam, the gate proper being mounted on the carriage for pivotal movement about a vertical axis.

General experience with load dividing gates has shown that under some conditions the sprocket teeth may fail, permitting the suspension to become oblique with respect to the supporting rails. It is then possible for the gate structure to become detached from the rails, risking injury to an operator and damage to cargo.

The present invention avoids that possibility by forming the rail and the gate-supporting rollers in such a way that the rollers are trapped within a chamber of the rail structure. That is not, however, sufficient in itself if the rollers are journaled on the gate brackets with freedom of axial movement, as is preferred to accommodate slight variations in mutual spacing of the supporting rails, since the trapped roller might then merely pull free of the bracket. To avoid that possibility, the present invention further provides stop means for positively retaining the sprocket wheels on the squaring shaft, and provides positive axial coupling between each roller and the corresponding sprocket wheel. That overall combination effectively prevents release of the gate despite failure of the sprocket teeth.

The application of some of those features to gate suspensions of more conventional type, in which the squaring shaft is above the rails and directly carries the gate-supporting rollers as well as the toothed sprocket formations, is described and claimed in the copending patent application of Paul W. Pettigrew and the present applicants, Ser. No. 721,511, filed Apr. 15, 1968, now U.S. Pat. No. 3,549,291.

A full understanding of the invention, and of its further objects and advantages, will be had from the following description of a preferred manner of carrying it out. The particulars of that description, and of the accompanying drawings which form a part of it, are intended only as illustration and not as a limitation upon the scope of the invention, which is defined in the appended claims.

In the drawings:

FIG. 1 is a transverse section representing a vehicle lading compartment with a load dividing gate embodying the invention;

FIG. 2 is a fragmentary section corresponding to a portion of FIG. 1 at enlarged scale; and

FIG. 3 is a section on line 3--3 of FIG. 2.

FIG. 1 represents in schematic transverse section a typical lading compartment 10 of a railway freight car, with left and right sidewalls 12 and 13, floor 14 and ceiling 15. The load dividing gate 20 is suspended from the fixedly mounted left and right rails 30 and 32 by means of the rollers 50 and 52 which ride on horizontal rail flanges. Such mounting facilitates movement of the gate longitudinally of the car between selected working positions, or between such working positions and a storage position, typically against an end wall of the compartment. The gate is locked in a selected position by the upper locking pins 40 and 42 and the lower locking pins 41 and 43, which are releasably engageable with locking formations in the rails already described and in the locking strips 46 and 48 set into the compartment floor. The locking pins are controlled in conventional manner by the handle 44 and the crankshaft 45.

The present gate and its suspending mechanism are designed to clear the overhead obstruction indicated schematically at 18. That obstruction extends longitudinally of the compartment along the central portion of the ceiling, and may typically comprise an air duct that is part of the air-conditioning equipment. Since the obstruction 18 typically does not extend laterally all the way to the sidewalls, it is desirable to place the gate-supporting rails in the available spaces at each side of the obstruction and above its lower surface, where they do not interfere with the cargo. With that rail placement the central obstruction 18 prevents the use of conventional squaring mechanism, by which the gate-supporting rollers normally include rail-engaging sprocket teeth and are mounted on a common squaring shaft to maintain the gate structure at right angles to the rails as it moves along them. However, as described in the above-identified patent, that difficulty may be avoided if the gate-supporting rollers are freely journaled on brackets 60 and 62 that extend upwardly from the gate, and the squaring shaft 70 is journaled on those brackets below the rails and clear of the overhead obstruction. Sprockets on the squaring shaft can then engagingly ride the lower faces of the rails, and are not required to carry the weight load of the gate.

FIGS. 2 and 3 show at enlarged scale the section of the suspension mechanism associated with rail 30, together with a portion of the corresponding mechanism associated with rail 32. Except for certain details of that section, to be described, the two sections of the suspension mechanism may be identical. Rail 30 is secured to the compartment ceiling, as by the bolts 31, and comprises the vertical web portion 34, the relatively wide lower horizontal flange 36, and the upper horizontal flange 38, the edge of which is bent down to form the lip 39. The roller 50 is freely journaled on the bracket 60, comprising the bracket arm 64, mounted on the gate by structure to be described. As shown, the stub shaft 53 is rigidly mounted on bracket arm 64, as by welding, and forms a plain bearing on which roller 50 is freely movable both in rotation and in translation. Roller 50 has the main load-bearing surface 54 which comprises two cylindrical surfaces of equal radius separated by the channel 55 which provides clearance for the sprocket teeth, to be described. Axially outward of surface 54 is a relatively wide and deep channel 56 which provides clearance for the ends of locking pins 40. At the outer end of roller 50 is the flange 58, the radius of which is preferably slightly less than that of load-bearing surface 54, so that flange 58 is normally spaced from the upper surface of rail flange 36 by a distance of the order of one-sixteenth inch. That spacing is selected in known manner so that the gate load is normally carried entirely by the dual surface 54, but that an excessive load imposed by shock conditions is shared by the surface 58 before the rail flange 36 is deflected beyond its yield point.

The squaring shaft 70 is journaled in bracket arm 64 directly below stub shaft 53, typically in a bushing 74 of Teflon or similar material, and is similarly journaled on the bracket mechanism 62 at the other end of the gate. The sprocket wheel 80 is mounted in rotationally fixed relation on the end of shaft 70, with its sprocket teeth 84 engaging a series of apertures 85 formed in rail flange 36, so that movement of bracket 60 along the rail is necessarily accompanied by corresponding rotation of sprocket wheel 80 and squaring shaft 70. A similar relation applies to the other end of the squaring shaft, which carries the sprocket wheel 82 geared to rack teeth 85 on rail 32. Hence the two ends of the gate can move along their respective rails only in unison, maintaining the gate at right angles to the rails.

One of the sprocket wheels 82 is preferably pinned rigidly to squaring shaft 70 as indicated at 87, while the other wheel 80 is mounted in splined relation to the shaft to permit free axial movement within a limited range. For example, as shown in FIG. 2, sprocket 80 is keyed to shaft 70 by the Woodruff key 76, which is set in a fitting recess in the shaft and works in an axial keyway 78 in the sprocket bore. The sprocket is positively prevented from sliding off the end of shaft 70 by the steel block 79, which is inserted in the axially inner end of keyway 78 and welded in place. With that construction, the axial position of shaft 70 is defined by engagement of the pinned sprocket wheel 82 with rail 32. Any normal variations in the spacing between the two rails are accommodated by axial sliding of sprocket 80 on shaft 70, insuring that both sprockets can freely ride the rack formations on the underside of their respective rail flanges. Shaft 70 is journaled on bracket 64 in fixed axial relation, as by the spacing collar 71 and retaining ring 73, thus defining the lateral position of the gate structure with respect to rail 32. At bracket 60, on the other hand, shaft 70 is journaled with sufficient axial freedom to accommodate slight relative movements of the two bracket structures.

A further important feature of the present structure is provided by the positive axial coupling between the sprocket wheel and the load-bearing roller associated with each rail, in combination with rail structure for positively trapping the roller in rail engagement. As illustratively shown, the sprocket and roller are coupled axially by means of the radial sprocket flange 86, which is freely received in the roller channel 88. That channel is formed axially inward of load-bearing surface 54 and is terminated at its inward end by the radial roller flange 89. Sprocket flange 86 is spaced from the sprocket teeth 84 just sufficiently to clear the edge of flange 36 of the supporting rail. That coupling between sprocket and roller allows the roller only as much actual freedom of axial movement on its stub shaft 53 as the sprocket has on squaring shaft 70, in view of the limiting block 79. That limitation positively prevents the roller from sliding off its stub shaft.

Each load-bearing roller is positively held in supporting relation on the rail by trapping of its axially outer flange 58 within the elongated chamber 90 that is formed by the rail configuration. The rail lip 39 forms with lower rail flange 36 a chamber mouth that is narrower than the diameter of roller flange 58, already described. Although lip 39 does not interfere with normal operation of the roller, it positively traps the roller flange in chamber 90, preventing the roller from leaving the rail.

With that structure, even if one or more of the sprocket teeth 84 should fail completely, disabling the normal tracking action of those teeth in the rail apertures 85, the suspension cannot come free of the supporting rail. For the coupling between sprocket and roller positively prevents the roller from sliding off its stub shaft, and the roller is retained on the rail by lip 39. Hence the suspension remains in supported relation to the rail.

In the presently preferred form in which the sprocket wheel 82 is directly pinned to squaring shaft 70, the corresponding roller 52 requires relatively little axial play on its stub shaft 53. Hence mechanism of any convenient type can be employed for positively retaining the roller on that shaft. As illustrated, that mechanism includes interengaging flanges on the sprocket wheel and roller similar to that already described.

A further aspect of the invention concerns the means for providing convenient adjustment of the lateral position of the lower edge of the gate with respect to the compartment floor. Such adjustment is sometimes needed to compensate inaccuracies in the car structure and to bring the lower locking pins 41 and 43 into alignment with the respective strips 46 and 48. Such adjustment can be provided by swinging the entire gate in its own plane around one of the supporting rails. In absence of an overhead obstruction the squaring shaft normally carries directly the load-bearing rollers. The described adjustment can then be produced by simple adjustment of one or both shaft journals relative to the brackets at the respective ends of the gate, as described in U.S. Pat. No. 3,464,369, issued on Sept. 2, 1969 to John W. Erickson, one of the present applicants, and assigned to the same assignee as the present application. That solution cannot be applied in a suspension of the present underslung configuration. In accordance with the present invention, suitable lateral gate adjustment is provided in suspensions of underslung type by particularly effective structure for bodily shifting the entire supporting brackets relative to the gate structure.

As shown illustratively in FIG. 2 for bracket 60, a support shaft 66 is rigidly secured to each of the bracket arms 64 near its lower end and parallel to squaring shaft 70 and stub shaft 53. Shaft 66 thus forms with the bracket arm and stub shaft 53 a rigid bracket assembly. Shaft 66 is journaled on the gate structure by means of two plain bearings 94 and 96. Outer bearing 94 is close to the bracket arm and is vertically adjustable relative to the gate. Inner bearing 96 is near the inner end of shaft 66 and is fixed with respect to the gate structure. Adjustment of the movable bearing then causes the bracket assembly to swing about the fixed bearing through a small angle, raising or lowering the load-supporting roller 50 or 52 with respect to the gate. An important advantage of that adjustment mechanism is that it does not affect the relationship between the roller and the sprocket, so that their cooperation with the rail remains as already described. The slight change of inclination of the bracket assembly that accompanies such adjustment does not significantly disturb that cooperation, and is readily accommodated with respect to squaring shaft 70 by providing a suitable small clearance between that shaft and the inner diameter of bushings 74. Similarly, a suitable clearance is provided in fixed bearing 96.

Any suitable structure may be employed for providing the small amount of vertical adjustment required for movable bearing 94. A particularly effective and convenient structure comprises a large bushing 100 having its bore 101 offset eccentrically with respect to its outer cylindrical surface 102 (FIG. 3). The bushing is mounted on the gate structure in rigid but rotatably adjustable position. In the present illustrative structure the bushing is rotatably received in a bore in the rigidly mounted platelike support post 106, which is reinforced by the shroud 107. A defining plate 103 is rigidly mounted on the bushing and flatly engages a face of post 106, to which it is secured in a selected rotary position by the bolt 108. A single hole is preferably provided in post 106 and a plurality of holes 109 are provided in plate 103 angularly spaced about the bushing. In practice three such holes are normally sufficient, corresponding to three bushing angles spaced at 90° intervals, as shown in FIG. 3. Fixed bearing 96 typically comprises a simple bore in a vertical post 110, that bore being a few thousandths oversize to permit the described shaft adjustment.

That structure for mounting suspension brackets 60 and 62 has the advantage that the brackets are freely swingable with respect to the axes of support shafts 66, which axes can be considered coincident for most purposes. That freedom permits bracket arms 64 to remain essentially vertical despite swinging of the gate as the latter is manually pushed along rails 30 and 32, thus preventing any tendency for the mutually opposed sprockets and rollers to exert a clamping action on the rail flanges. It is generally advantageous to maintain the two bracket arms 64 parallel to each other during such swinging of the gate. That may be accomplished, for example, by coupling the two support shafts 66 together, as by the intermediate shaft section indicated at 120. A universal joint 122 is interposed between coupling shaft 120 and each of the support shafts to accommodate the slight variations in direction of the support shafts that results from the adjustment capability described in connection with FIG. 3. The length of each shaft 66 between its bearings 94 and 96 is preferably short enough to provide the required rigidity against deflection in response to dynamic load variations without excessive shaft dimensions, and yet long enough to limit to a convenient value the change in shaft direction as bearing 94 is adjusted. An illustrative separation of bearings 94 and 96 is about 1 foot. Coupling shaft 120, if used, is then typically of the order of 6 feet long. On the other hand, under certain conditions, the two support shafts may be made so long that the inner bearings 96 for the two shafts are close together. The coupling structure may then comprise a single universal joint directly coupling the two support shafts. Such a single universal joint may comprise merely a thinned section of a unitary shaft, and a single centrally placed bearing may act as inner bearing for both sections of such a shaft.

The invention is useful both in connection with gates that are always parallel to the axis of the squaring shaft, as in the illustrative embodiment described above, and in connection with gates mounted for pivotal movement about a vertical axis and translational movement longitudinally of the squaring shaft. Thus, the upper part of the gate 20 in FIG. 2 may be considered to represent a beam on which brackets 60 and 62 are mounted as already described; and the gate proper may be mounted on such a beam in known manner for relative pivotal and translational movement. In the present claims the term "gate structure" is intended to include such a beam and structure for mounting the gate from the beam, if used.