GB2081198A

GB2081198A - Hopper Door Mechanisms, e.g. for Railway Wagons

Info

Publication number: GB2081198A
Application number: GB8121100A
Authority: GB
Original assignee: Gloucester Railway Carriage and Wagon Co Ltd
Current assignee: Gloucester Railway Carriage and Wagon Co Ltd
Priority date: 1980-07-18
Filing date: 1981-07-08
Publication date: 1982-02-17
Also published as: GB2081198B

Abstract

Two door assemblies 13, 14 are pivotally mounted on the hopper 10 by support arms 16, 19 whereby each door may be swung into and out of a position where it closes a discharge opening 11, 12 in the lower part of the hopper. An operating mechanism 21 is provided for imparting swinging movement to one of the door assemblies 13, and toggle linkages 35 connect that door assembly to the other door assembly 14 so as to transmit corresponding swinging movement from said one door to the other, both the operating mechanism 21 and the toggle linkages 35 being located externally of the hopper. <IMAGE>

Description

SPECIFICATION Improvements in Hopper Door Mechanisms The invention relates to hopper door mechanisms and particularly, but not exclusively, to hopper door mechanisms for use on railway hopper wagons.

In door mechanisms for railway hopper wagons there are usually provided, on the lower part of the hopper, two symmetrically disposed doors which are pivotable towards and away from one another to close and open the discharge opening at the bottom of the hopper.

In one known form of door mechanism, the doors are mounted on swinging support arms for pivoting movement about axes spaced above the doors so that the doors are swung sideways towards one another to close the discharge opening of the hopper. The swinging movement of the doors may be effected by a manually operated mechanism or by a power operated mechanism, for example employing pneumatic rams. In the latter case, however, it has hitherto been necessary to provide a separate ram to operate each door. Due to limitations as to the extent to which such rams may project in a direction transversely of the hopper wagon, the permitted stroke of the rams is, in practice, limited with the result that, with previously known mechanisms, the opening movement of the doors, and hence their width, must be kept comparatively small.It is an object of the invention to provide an improved hopper door mechanism whereby both doors are operated by a single mechanism so that in the case where a pneumatic ram is used, only a single ram is required and this may therefore have a longer stroke than has been the case hitherto, thus permitting the use of larger hopper doors.

According to the invention there is provided a hopper door mechanism comprising two door assemblies, each door assembly comprising a door carried by at least one swinging support arm having one end thereof connected to the door and the other end thereof mounted on the hopper for pivoting about an axis, whereby each door may be swung about said axis into and out of a position where it closes a discharge opening in the lower part of the hopper, an operating mechanism for imparting said swinging movement to one of said door assemblies, and a linkage connecting said one door assembly to the other door assembly in a manner to transmit corresponding swinging movement from said one door to the other, both the operating mechanism and the linkage being located externally of the hopper.

It will be appreciated that since the operating mechanism operates directly on only one of the door assemblies it does not require to be symmetrically disposed with respect to the assemblies. The mechanism can therefore be located externally of the hopper and to one side thereof, and may, for example, be operated by a single pneumatic ram extending across the end of the hopper to the opposite side thereof. A ram of long stroke may therefore be used, permitting large opening movements of the doors.

The operating mechanism for imparting swinging movement to said one door assembly may comprise a lever arm pivotable about an axis which is fixed in relation to the hopper, the free end of the lever arm being connected by a link to said one door assembly, and the lever arm being connected to means for imparting swinging movement thereto. For example, the means for imparting swinging movement may be operable on a further lever arm connected to the first said lever arm so as to rotate therewith about a common axis.

Said means for imparting swinging movement to the first said lever arm may comprise an element coupled to the lever arm and in screw threaded engagement with a rotatable threaded rod, whereby rotation of the rod effects movement of the element therealong and imparts swinging movement to the lever arm.

Alternatively said means for imparting swinging movement to the first said lever arm may comprise a pneumatic ram.

Each hopper door may be carried by two spaced swinging support arms, the opposite ends of the arms being pivotally connected about parallel spaced axes to the door and hopper respectively.

In any of the above arrangements, the linkage connecting the door assemblies may comprise a double-armed crank pivotable about an axis which is fixed in relation to the hopper, opposite ends of the crank arms being connected to the two door assemblies respectively by pivotable links. Preferably, the pivotal connections between said links and the door assemblies respectively are adjustable.

Preferably, the relative positions of the pivotable connections between the link connected to said other door assembly and the crank and door aesembly respectively are such that the crank and link form a toggle mechanism which passes through an overcentre position as the door is moved to its closing position. Thus, once the mechanism has been moved to the closing position, it cannot be moved to the open position merely by pressure of material in the hopper on the doors. Such pressure will tend to hold the mechanism more firmly in the closed position, and the doors may only be opened by positive operation of the operating mechanism.

Where such an overcentre toggle mechanism is provided, the operating mechanism for imparting swinging movement to said one of the door assemblies may include a lost motion connection, there being connected to the other door assembly spring means adapted to urge the other door assembly towards the open position against the action of said toggle mechanism, which spring means are coupled to the operating mechanism so as to be energized as the lost motion is taken up, whereby when the lost motion has been taken up and the operating mechanism has imparted sufficient swinging movement to said one door assembly to release the toggle mechanism from its overcentre position, said other door assembly, and hence also said one door assembly, is moved rapidly to the open position by the spring means.

The invention includes within its scope a hopper, in particular a hopper on a railway wagon, including a door mechanism of any of the kinds referred to above.

The following is a more detailed description of embodiments of the invention, reference being made to the accompanying drawings in which: Figure 1 is a diagrammatic end elevation of a hopper door mechanism for a railway wagon, Figure 2 is a diagrammatic side elevation of the mechanism shown in Figure 1, Figure 3 is a diagrammatic end elevation of an alternative form of hopper door mechanism, Figure 4 is a diagrammatic end elevation of a further form of hopper door mechanism, Figure 5 is a diagrammatic side elevation of the mechanism shown in Figure 4, and Figure 6 is a diagrammatic end elevation of a still further form of hopper door mechanism.

In the drawings of the various embodiments, corresponding parts bear the same reference numerals.

Referring to Figures 1 and 2, the hopper, the side walls of which are indicated at 10, is formed at its lower end with discharge openings 11 and 12 with which are associated swinging door assemblies 13 and 14 respectively.

Each door assembly 13 comprises a door 1 5 supported by two swinging support arms 16 located externally at opposite ends of the hopper and pivotally supported at 17 on the hopper.

Similarly, the door assembly 14 comprises a door 18 supported by two swinging support arms 19 pivotally mounted at 20 at opposite ends of the hopper. Thus the doors 15 and 1 8 may be swung on the arms 1 6 and 19 respectively into and out of the closed position shown in the drawings.

Swinging movement is imparted to the door mechanism 1 3 by means of an operating mechanism indicated generally at 21. The operating mechanism comprises a cylindrical sleeve 22 which is rotatable on a fixed horizontal shaft 23 the opposite ends of which are secured to brackets 24 mounted on the hopper. Adjacent one end of the sleeve 22 there is secured thereto a lever arm 25 the free end of which is pivotally connected to one end of a short link 26 the other end of which is pivotally connected to a sleeve 27 which is in threaded engagement with a screwthreaded portion 28 of a horizontal operating shaft 29. The shaft 29 extends transversely of the hopper wagon and is supported on brackets 30.

Manipuiating wheels 31 are provided on opposite ends of the shaft 29 and it will be appreciated that rotation of either of the wheels 31 will cause longitudinal movement of the sleeve 27 along the threaded portion 28, which movement, in turn, effects pivoting movement of the arm 25 and rotation of the sleeve 22.

The opposite end of the sleeve 22 to that carrying the lever arm 25 is disposed adjacent the central portion of the door assembly 13 and carries a further lever arm 32. The free end of the lever arm 32 is pivotally connected to one end of a link 33 the opposite end of which is pivotally connected to the door 1 5 by a connector 34.

Thus, the arrangement is such that rotation of the, sleeve 22, effected by turning either of the wheels 31, imparts swinging movement to the link 32 which, in turn, imparts swinging movement ta the door 15.

At each end of the hopper each support arm 1 6 of the door assembly 1 3 is connected to the corresponding support arm 19 of the door assembly 14 by a linkage indicated generaliy at 35. Each linkage 35, which is disposed extemally of the hopper wall, comprises a double-ended crank 36 rotatably mounted on the end wall of the hopper and links 37 and 38 which pivotally connect the ends of the crank 36 to the support arms 1 6 and 1 9 respectively. As best seen in Figure 1, outward swinging movement of the door assembly 13 to the open position causes clockwise rotation of the crank arm 36, through the links 37, and the links 38 transmit this clockwise rotation to the door assembly 14.The links 38 are angled as shown and the relative positions of the pivotal connections at the ends of the links 38, and of the axis of rotation of the crank arm 36, are such that when the door assemblies are in the closed position the crank arm 36 and link 38 act as a toggle mechanism, passing through an overcentre position so as, effectively, to lock the hopper doors in the closed position whereby the doors do not tend to be opened by pressure of material in the hopper.

To permit fine adjustment of the closed positions of the doors, the ends of the links 37 and 38 are not directly connected to the respective support arms 1 6 and 1 9 but are connected thereto through adjustment devices 39. Each adjustment device comprises an arm 40 pivotally mounted at one end on the support arm of the door assembly and provided at its opposite end with a bolt 41 which passes through an arcuate slot 42 in the associated support arm. The associated link 37 or 38 is pivotally connected to the arm 40 intermediate its ends. Thus the location of this pivotal connection in relation to the door support arm may be adjusted by loosening the bolt 41, adjusting the angular position of the arm 40 by sliding the bolt along the arcuate slot 42, and then retightening the bolt.

In the alternative arrangement shown in Figure; 3 the operating mechanism 21 of the embodiment of Figures 1 and 2 is replaced by a pneumatic ram 43, the cylinder 44 of which is pivotally mounted on a bracket 45 fixed to the hopper and the piston rod 46 of which is pivotally connected to a bracket 47 on the hopper door 1 5.

Accordingly, the door assembly 13 is swung to the open position by retraction of the ram 43 and is closed by extension of the ram. The swinging movement of the door assembly 1 3 is transmitted to the other door assembly 14 through the toggle linkages 35 as in the arrangement of Figures 1 and 2.

As previously mentioned, the hopper door mechanism according to the invention permits the operation of the mechanism by a single pneumatic ram extending across a substantial part of the width of the wagon and such an arrangement is shown in Figures 4 and 5.

In this arrangement the door assembly 13 comprises, at each end of the hopper, two swinging support arms 48 and 49 which are pivotally connected at their upper ends to a fixed bracket 50 and at their lower ends to the door 1 5.

The pivot axes of the two arms are parallel and spaced apart on the bracket 50 and door 1 5 respectively.

Similarly the door assembly 14 comprises, at each end of the hopper, two swinging support arms 51 and 52 pivotally connected at their upper ends to a bracket 53 and at their lower ends to the door 18. The support arms 49 and 52 of the two assemblies are interconnected by toggle linkages 35 similar in construction to the corresponding linkages in the previously described arrangements.

In the arrangement of Figures 4 and 5, however, the operating mechanism 21 comprises, at each end of the hopper, a link 54 one end of which is pivotally connected to the support arm 48, as indicated at 55, and the other end of which is pivotally connected to a lever arm 56 secured to a shaft 57 which extends longitudinally of the hopper, as shown in Figure 5, and is rotatably supported in fixed bearings 58 at opposite ends of the hopper.

Secured to the shaft 57 beyond one end of the hopper is a double lever arm 59 the free end of which is pivotally connected at 60 to the piston rod 61 of a pneumatic ram 62. The cylinder 63 of the ram 62 is fixedly mounted in relation to the hopper so as to extend partly across the width thereof as shown in Figure 4.

Extension of the ram 62 swings the lever arm 59 anticlockwise, as viewed in Figure 4, rotating the shaft 57 anticlockwise and thus swinging the lever arms 56 upwardly. The upward movement of the lever arms 56 swings the door assembly 13 outwardly towards the open position and this opening movement is transmitted to the other door assembly 14 through the toggle linkages 35.

The piston rod 61 is connected to the lever arm 59 by a pin and slot connection so as to permit the upward swinging movement of the lever arm.

It will be appreciated that the manually operated arrangement shown in Figures 1 and 2 results in the hopper doors opening fairly slowly, since the speed of opening is dependent on the speed at which the shaft 29 can be rotated by an operator. In some circumstances, however, it is desirable for the hopper doors to open rapidly to their maximum extent, for example in the case where the contents of the hopper are such that they tend to coagulate. Figure 6 shows an operating mechanism which effects rapid opening of the hopper doors.

In this case, the door assemblies 13 and 14 each comprise two swinging support arms, at each end of the hopper, as in the arrangement of Figure 4, and the toggle linkages 35 are also similarly arranged.

The operating mechanism 21 is also similar to the corresponding mechanism of Figure 4, but in the Figure 6 arrangement the upper free end of the lever arm 59 carries a transverse pin 64 which engages within a longitudinal slot 65 in a link 66 which is pivotally mounted at 67 on a sleeve 68.

The sleeve 68 is in screw-threaded engagement with a threaded portion of a shaft 69 which extends transversely of the hopper at one end thereof. Manipulating wheels 70 are provided at opposite ends of the shaft 69 for effecting its rotation.

A helical tension spring 71 is connected between an extension 72 on each support arm 51 of the door assembly 14 and the free end of a curved lever arm 73 mounted on a shaft 74 which extends longitudinally of the hopper and is rotatable in fixed bearings at opposite ends thereof. Secured to the shaft 74 at the same end of the hopper as the lever arm 59 is a further lever arm 75 which is connected,by means of a pin and slot connection 76, to a further sleeve 77 which is in screw-threaded engagement with a further threaded portion of the shaft 69. The threaded portion of the shaft 69 engaged by the sleeve 68 is oppositely handed to the threaded portion engaged by the sleeve 77 so that when the shaft 69 is rotated the sleeves 68 and 77 move towards or away from one another, depending on the direction of rotation of the shaft 69.

When it is wished to open the hopper doorsthe shaft 69 is rotated in a direction to move the sleeves 68 and 77 away from one another. The movement of the sleeve 68 to the left, as seen in Figure 6, initially has no effect on the lever arm 59 since the slot 65 and pin 64 act as a lost motion connection. However, the movement of the sleeve 77 to the right swings the lever arm 75 clockwise, thus rotating the shaft 74 clockwise also and swinging the lever arms 73 upwardly so as to tension the springs 71. The tensioning of the springs 71 thus applies a preloading to the door assembly 14 tending to urge the door assembly towards the open position. However, the door assembly is prevented from moving to the open position due to the overcentre arrangement of the toggle linkages 35.

After a predetermined movement of the sleeves 68 and 77, by which time the springs 71 are preloaded to a required amount, the end of the slot 65 engages the pin 64 on the lever arm 59 so that continued movement of the sleeve 68 causes anticlockwise swinging movement of the lever arm 59, and thus the anticlockwise rotation of the shaft 57 and upward swinging movement of the lever arms 56. This begins to move the door assembly 1 3 outwardly from its closed position and thus rotates the toggle linkages 35 from the overcentre position shown in Figure 6.

As soon as the toggle linkages 35 are moved from the overcentre position the tension in the springs 71 causes the door assembly 14 to swing rapidly outwardly to the open position and this movement is transmitted through the toggle linkages 35 to the door assembly 13. The rapid outward movement to the open position of the door assembly 1 3 transmits anticlockwise rotation to the shaft 57 and the lever arm 59, but this movement of the lever arm 59 is permitted by movement of the pin 64 to the left along the slot 65.

The door assemblies may be closed again by reversing the rotation of the shaft 69.

In each of the arrangements described above the door assemblies 13 and 14 are interconnected by toggle linkages which pass through an overcentre position as the doors are closed, and this arrangement is preferred since it means that the downward pressure of material in the hopper tends to hold the door mechanism more tightly closed. However, it will be appreciated that other forms of mechanism may be used to interconnect the door assemblies 13 and 14. For example, in the arrangement of Figures 1 to 3, the support arms 16 and 19 may be interconnected by a meshing gear arrangement.Thus the support arm 1 6 may have connected thereto a gear wheel, or sector of a gear wheel, which is rotatable with the support arm 1 6 about its pivotal axis 1 7 and engages with a similar gear wheel or gear sector rotatable with the swinging support arm 1 9. Instead of the gears or gear sectors on the two support arms being directly engaged with one another, they may be interconnected by a train containing an even number of further gears. In each case the arrangement is such that outward swinging movement of the support arm 1 6 is accompanied by corresponding outward swinging movement of the support arm 19.

Alternatively, the support arm 1 6 may be provided with an upward extension which projects above the pivot axis 17, there being pivotally connected to this extension one end of an inclined link the opposite end of which is pivotally connected to a point on the support arm 19 below the pivot axis 20. Thus, outward swinging movement of the support arm 1 6 will move the link to the right thus transmitting corresponding outward swinging movement to the support arm 19.

Similar alternative arrnagements to those just described may be provided between the support arms 49 and 52 in the arrangements of Figures 4, 5 and 6.

Claims

1. A hopper door mechanism comprising two door assemblies, each door assembly comprising a door carried by at least one swinging support arm having one end thereof connected to the door and the other end thereof mounted on the hopper for pivoting about an axis, whereby each door may be swung about said axis into and out of a position where is closes a discharge opening in the lower part of the hopper, an operating mechanism for imparting said swinging movement to one of said door assemblies, and a linkage connecting said one door assembly to the other door assembly in a manner to transmit corresponding swinging movement from said one door to the other, both the operating mechanism and the linkage being located externally of the hopper.

2. A mechanism according to claim 1, wherein the operating mechanism for imparting swinging movement to said one door assembly comprises a lever arm pivotable about an axis which is fixed in relation to the hopper, the free end of the lever arm being connected by a link to said one door assembly, and the lever arm being connected to means for imparting swinging movement thereto.

3. A mechanism according to claim 2, wherein the means for imparting swinging movement to the lever arm are operable- on a further lever arm connected to the first said lever arm so as to rotate therewith about a common axis.

4. A mechanism according to claim 2 or claim 3, wherein said means for imparting swinging movement to the first said lever arm comprises an element coupled to the lever arm and in screw threaded engagement with a rotatable threaded rod, whereby rotation of the rod effects movement of the element therealong and imparts swinging movement to the lever arm.

5. A mechanism according to claim 2 or claim 3, wherein said means for imparting swinging movement to the first said lever arm comprises a pneumatic ram.

6. A mechanism according to claim 1, wherein the operating mechanism for imparting swinging movement to said one door assembly comprises a pneumatic ram connected between said assembly and a fixed part.

7. A mechanism according to any of the preceding claims, wherein each door is carried by two spaced swinging support arms, the opposite ends of the arms being pivotally connected about parallel spaced axes to the door and hopper respectively.

8. A mechanism according to any of claims 1 to 7, wherein the linkage connecting the door assemblies comprises a double-armed crank pivotable about an axis which is fixed in relation to the hopper, opposite ends of the crank arms being connected to the two door assemblies respectivejy by pivotable links.

9. A mechanism according to claim 8, wherein the pivotal connections between said links andthe door assemblies respectively are adjustable.

10. A mechanism according to claim 8, wherein the end of each link is pivotally connected to a short connecting link fixed to the door assembly but angularly adjustable with respect thereto.

11. A mechanism according to any of claims 8 to 10, wherein the relative positions of the pivotable connections between the link connected to said other door assembly and the crank and door assembly respectively are such that the crank and link form a toggle mechanism which passes through an overcentre position as the door is moved to its closing position.

12. A mechanism according to claim 11, wherein the operating mechanism for imparting swinging movement to said one of the door assemblies includes a lost motion connection and wherein there is connected to the other door assembly spring means adapted to urge the other door assembly towards the open position against the action of said toggle mechanism, which spring means are coupled to the operating mechanism so as to be energised as the lost motion is taken up, whereby when the lost motion has been taken up and the operating mechanism has imparted sufficient swinging movement to said one door assembly to release the toggle mechanism from its overcentre position, said other door assembly, and hence also said one door assembly, is moved rapidly to the open position by the spring means.

13. A mechanism according to claim 4 and claim 12, wherein said threaded rod has rotatable therewith a further threaded portion with which a further element is in screw threaded engagement, the further elementbeing coupled to said spring means so that the movement of the further element along the further threaded portion, as the latter rotates, energises the spring means.

1 4. A hopper door mechanism substantially as hereinbefore described with reference to Figures 1 and 2, Figure 3, Figures 4 and 5 or Figure 6 of the accompanying drawings.

15. A hopper wagon including a hopper door mechanism according to any of the preceding claims.