Field of Search:
105/250,253,280,282R,282A,282P,305,38R,38P
Description:
BACKGROUND OF THE INVENTION
Gravity outlets for hoppers comprise a mechanism, such as a rack and pinion, for moving a horizontal gate back and forth to close and open the gate in order to discharge the lading therefrom. When such gravity outlets are used on hoppers in railroad cars, it is important to maintain the gate in closed position during transit. In this regard a locking shaft running transversely of the car and parallel to the pinion drive shaft has been provided having a locking arm thereon which, when rotated to the locked position, is designed to hold the gate in place and prevent it opening. Upon rotation of the shaft the gate can be opened by means of the pinion drive shaft.
However, under impact, such as coupling of cars and in transit over uneven tracks, the locking arm has been jarred out of the locked position, thus permitting the gate to open and discharge part or even all of the lading.
OBJECTS
It therefore is an object of the present invention to provide a means for maintaining the locking arm in locked position under impacts and/or during transit.
It is another object of the present invention to provide a means for maintaining the locking arm in locked position in a simple and economical manner.
Other objects will be apparent from the following description and drawings.
THE DRAWINGS
FIG. 1 is a perspective cut-away view of the gravity gate and locking system therefor of the present invention;
FIG. 2 is a top view of a gravity outlet gate and locking arrangement of the present invention;
FIG. 3 is a sectional view along the line 3--3 of FIG. 2;
FIG. 4 is a detail view of the locking cam and cam plate of the present invention; and
FIG. 5 is an enlarged view of another locking cam shape which could be utilized in accordance with the present invention.
FIG. 6 is a view of an alternative embodiment of the rigid member wherein the rigid member has a cross section in the form of an angle;
FIG. 7 is a view of an alternative embodiment of the rigid member wherein the rigid member comprises a rectangular tube in cross section;
FIG. 8 is a view of an alternative embodiment of the invention wherein the rigid member comprises a convex surface and an elliptical cam surface is utilized;
FIG. 9 is a perspective view of a portion of the outlet shown in FIG. 1 illustrating that rigid member 54 may extend only part way across the outlet.
DETAILED DESCRIPTION
As shown in the drawings, a gravity outlet indicated generally at 10 mounted on the car frame is shown having side slope sheets 12 and 14 and end slope sheets 16 and 18 which are welded or otherwise joined together. The slope sheet flanges 11 have bolt openings therein 15 for affixing the gate to a hopper of a railroad car, overland truck or other transportation vehicle.
A sliding gate indicated generally at 20 is provided having an elongate horizontal portion 22. The gate may have a tapered end portion 24 adapted to cooperate with tapered gate guides 17 in sealing the gate in closed position. The other end of the gate 20 may comprise a vertical portion 26 which in the closed position engages a combination pan stiffener and stop 13. The gate may be provided with means 110 for affixing the same to a discharge container or conduit indicated generally at 110. This means may comprise a channel 112 made integral with slope sheet 16 on the closed side of the outlet and a similar channel member 114 on the open side of the outlet.
Means for moving the gate horizontally into the open and closed positions are provided indicated generally at 30. In this regard one or more pinions 32 may be provided which drive racks 34 which are integrally affixed to gate 20 and move the gate into the open and closed positions. Pinions 32 may be driven by a pinion shaft 36 having mounted thereon a capstan 38. Capstan 38 may be rotated manually, or known motive power means attached to capstan 38 and/or shaft 36 to drive the pinions 32 automatically.
Mounted parallel with pinion shaft 36 and extending transversely of the car is a locking means indicated generally at 40 and comprising a locking shaft 42 having mounted thereon at least one locking arm 44 and may have at least one handle 41 thereon. Locking shaft 42 is held in place by means of supports 43. While two locking arms are illustrated in the drawings, it will be obvious that only one or any number of locking arms may be provided on shaft 42 as desired. In order to maintain gate 20 in the locked position, shaft 42 is rotated so that locking arm 44 engages an end portion of the gate to hold the same in closed position, for example, the end of racks 34 as shown in FIGS. 2 and 3. Rotation of the locking shaft 42 for example by means of handles 41 in the opposite direction to disengage locking arm 44 will allow the gate to be opened by the rack and pinion arrangement.
However, as mentioned above, the problem of the locking arm being jarred out of position during car coupling and during transit, which allows the gate to be wholly or partly opened by further jarring action is solved in accordance with the present invention by providing a locking cam arrangement indicated generally at 50. In accordance with the present invention a rigid member 52 is mounted parallel with locking shaft 42 all or part way across the car (as shown in FIG. 9). This rigid member is mounted at an incline with respect to the vertical and may as shown in the drawings, comprise an angle (FIG. 6), a rectangular tube (FIG. 7), or a T-member (FIGS. 4 and 5). Furthermore, at least one locking cam 54 is mounted upon locking shaft 42. While, if desired, more than one locking cam may be utilized, only one is illustrated in the drawings and only one is needed for effective operation of the locking arrangement. The locking cam and locking arm are so mounted on shaft 42 that upon rotating shaft 42 so that locking arm 44 engages the end of the gate 20 to hold the same in closed position, locking cam 54 moves along rigid cam plate 52 causing deflection of shaft 42 and/or rigid member 52. When the cam member reaches locked position shown in FIG. 3, shaft 42 assumes its undeflected position.
FIG. 4 illustrates in enlarged form, the camming action which takes place when shaft 42 is rotated to move locking arm 44 into the closed position. As locking arm 44 is moving into the closed position, locking cam 54 engages the lower surface of rigid cam plate 52(a). Specifically, cam surface 55 is moved along surface 52(a) as the shaft 42 deflects. Deflection will generally be at a maximum at about the mid-point 52b of surface 52. When the cam 54 reaches the position 52c deflection of shaft 42 will be essentially completed and no moment or stress will remain on shaft 42.
In general, it has been found that if at least about five foot-pounds of torque are required to move locking cam 54 from the engaged position shown in FIG. 4 that there will be very few, if any, occasions when jarring in transit can even partially open gravity gate 20.
In general, a bar diameter of from about one-half inch to two inches may be utilized for locking shaft 42. During engagement of locking cam 54 on plate 52 a deflection of about 1/8 to 1/2 inch may be utilized, depending upon the size of the bar and the distance from the locking cam to the nearest shaft support 43. In general, less deflection is required the nearer the locking cam is placed to the nearest shaft support 43. For example, with a 3/4 inch diameter bar with the locking cam about 2 feet from the lock shaft support a deflection of about 3/8 of an inch has been found to be satisfactory.
As indicated above, work of about 5 foot-pounds is sufficient to insure that the locking cam will maintain the locking arm in engagement with the gate and hence hold the gate in place. For manual rotation of shaft 42 for example by means of handles 41, a force of about 30 foot-pounds is believed to be of the approximate maximum amount of torque one man can exert without a bar. An amount of up to about 50 foot-pounds could be utilized if bars were utilized to rotate shaft 42. In this case a capstan 58 having an opening therein 59 would be provided at the end of locking shaft instead of handle 41, as shown dotted in FIG. 1.
In order to unlock the gravity outlet it is merely necessary to rotate locking shaft 42 in the opposite direction to overcome the torque and deflect the shaft 42 as cam 54 moves from position 52c to 52a in FIG. 4 and then out of engagement with rigid member 52. At the same time locking arm 44 is rotated out of position and the gate 20 may be moved to the open position for unloading, for example, by pinions 32.
Instead of the cam shape illustrated in FIG. 4, other cam shapes may be utilized to deflect shaft 42 and apply the locking torque. One example is shown in FIG. 5 wherein a semi-circular cam portion 55a is illustrated. If desired the cam, shape may be elliptical as shown in FIG. 8 at 55b. Other shapes for the cam surface will be apparent to those skilled in the art.
While surface of rigid member 52 has been illustrated as flat, it could have other shapes. For example, it could be made convex as shown in FIG. 8 at 57. Also, portions of rigid member 52 may deflect slightly in operation. Such variations will be apparent to those skilled in the art.