GB2359856A

GB2359856A - Apparatus for governing or damping the rotation of a shaft

Info

Publication number: GB2359856A
Application number: GB0012455A
Authority: GB
Inventors: Enda Keaveney
Original assignee: HIGHWAY INTERNAT Ltd
Current assignee: HIGHWAY INTERNAT Ltd
Priority date: 1999-10-08
Filing date: 2000-05-22
Publication date: 2001-09-05
Also published as: GB0012455D0; GB9923903D0

Description

1 2359856 J

DESCRIPTION OF INVENTION

4MPROVEMENTS IN OR RELATING TO A GOVERNOW THE PRESENT INVENTION relates to a governor, and more particularly relates to a governor adapted to govern the speed at which the shaft may rotate. In particular, the invention has an application in the field of a self-lifting or self-closing toilet seat, the governor being used to govern the rate of rotation of a shaft on which the toilet seat is mounted.

According to this invention there is provided a governor adapted to govern the speed of rotation of a shaft, the shaft being provided with a portion having an external projection, a follower being provided adapted to engage the external projection of the shaft, the projection or the follower presenting an inclined face inclined relative to the axis of the shaft, means being provided to constrain the follower to permit the follower to move axially whilst preventing the follower from rotating, the follower being connected to means which define part of a chamber, so that rotation of the shaft moves the follower which consequently moves the said means defining pail of a chamber to alter the volume of the chamber, means being provided defining a restricted air-flow passage communicating with the interior of the chamber.

2 In one embodiment the external projection comprises a helical thread and the follower is a nut.

In another embodiment the follower surrounds the shaft and defines a slot, engaged by the projection, which slot is inclined relative to the axis of the shaft.

Preferably the means defining a restricted air-flow passage to the interior of the chamber comprise an adjustable air bleed valve.

Conveniently the adjustable air bleed valve comprises a passage incorporating a conical tapering section and a flow regulating element inserted into said passage, the flow regulating element having a conical tapering portion within the conical tapering portion of the passage to define a relatively narrow, but adjustable, air-flow space therebetween.

Advantageously the means defining a chamber comprise a piston which is contained within a bore, the bore having a closed end, the chamber being defined between the piston and the closed end of the bore.

In a modified embodiment said restricted air-flow passage is provided communicating with the closed end of the bore, and a supplementary airflow passage, of greater diameter than the restricted air-flow passage, is provided communicating with pail of the bore which is spaced from the closed end of the bore. The governor may be incorporated in a toilet seat.

In order that the invention may be more readily understood, and so that further features thereof may be appreciated, the invenfion will now be 3 described, by way of exarnple, with reference to the accompanying drawings in which:

FIGURE 1 is a part-diagrammatic side view of a governor forming part of a self-closing toilet seat mechanism, illustrating the toilet seat in an upright position, FIGURE 2 is a top plan view corresponding to Figure 1, FIGURE 3 is a sectional view taken on line 111-IH of Figure 1 and Figure 3, FIGURE 4 is a side view of a piston forming part of the apparatus in Figures 1 to 3, FIGURE 5 is an exploded view of an air-bleed valve forming part of the governor of Figures 1 to 3, FIGURE 6 is a side view of a component of the air-bleed valve, and FIGURE 7 is a diagrammatic view illustrating part of a modified embodiment of the invention, and FIGURE 8 is a view of a modified embodiment of the invention.

Referring initially to Figures 1 to 3 of the accompanying drawings, a governor is illustrated, which is incorporated within a toilet seat mechanism.

4 Referring initially to Figure 1, a support 1 is provided incorporating a base plate 2 adapted to be secured to a toilet pan by an appropriate linkage. The base plate 2 has two upstanding arms 3, 4, and a shaft 5 extends between and is rotationally supported by the arms 3 and 4, the shaft extending outwardly on either side of the arms 3 and 4 The portion of the shaft 5 between the arms 3 and 4 is connected to a lug 6, the lug 6 being formed integrally with a toilet seat. The lug 6 is mounted fast with the shaft 5, and co-rotates with the shaft 5.

The end of the shaft 5 that extends beyond the arm 4 is provided with a coarse pitch thread 7. The threaded portion 7 on the shaft 5 is received within a threaded bore 8 formed within a square nut 9. The nut 9 is provided, at its lower edge, with a depending lug 10, as can be seen most clearly in Figure 3, the lug 10 being received within a channel 11 provided in an upstanding projection 12 on the base plate 2. The arrangement is such that the nut 9 may move axially relative to the axis of the shaft 5, but may not rotate. The nut may move 20 min per turn of the shaft.

The nut and thread comprise one example of a follower which is mounted on the shaft for axial movement relative to the shaft which is adapted to engage an external projection on the shaft, and it can be seen that in this example, both the helical threading on the shaft and also the cooperating helical threading on the nut present inclined faces which are inclined relative to the axis of the shaft. The consequence of the engagement between the external threading on the shaft and the internal threading present on the nut, is to cause the nut to move axially relative to the shaft in response to a rotational movement of the shaft.

The nut 9 is connected, by means of a connector 13 to a piston 14. An upstanding plate 15 is provided on the base 2. The plate 15 defines a bore 16 which receives the piston 14. The bore 16 has a closed end provided with an air-bleed valve 17.

A spring 18 is provided located between the lug 4 and the nut 12. The spring is a helical spring surrounding the shaft 5.

As shown in Figure 4, the piston 14 is provided with a stalk canying a generally flat transfers head 18 which terminates with a terminal radially outwardly extending flexible lip or skirt 19. The arrangement is such that as the piston 14 is introduced into the bore 16, the resilient skirt 19 may flex inwardly permitting gas to escape from the bore. However, when subsequently an attempt is made to withdraw the piston from the bore, thus moving the piston towards the left, as shown in Figures 1 and 2, the resilient skirt 19 would be biased outwardly and engage the side of the bore. Thus the piston will only be able to move as air is drawn into the chamber defined between the piston 14 and the closed end of the bore 11 through the bleed-valve 17.

The diameter of the bore 16 may be selected in dependence on the way to the toilet seat, with a large diameter bore of, for example, 32 nun being used for a heavy toilet seat such as wood is used, and a smaller diameter bore of, for example, 29 nun, being used if a light-weight plastic toilet seat is used.

Turning now to Figures 5 and 6, the bleed valve 19 is shown in greater detail. The bleed valve comprises a body member 20 provided at one end with exterior ribbing 21 to enable the body member to be secured in position. A through passage 22 is defined within the body member, the through passage having successive sections of reducing diameter.

6 An air control member 23 is provided having a leading substantially conical portion 24 adapted to be received as an almost air-tight fit within a conical portion of the through passage 22, and having a main threaded body section 25 which is bifurcated by means of an axially extending slit 26. The threaded section 25 may be received within a corresponding threaded portion of the passage 22. The position of the member 23 may be adjusted so that a predetermined quantity of air may flow through the slit 26 to the exterior of the tapering portion 24 of the member 23 and may then flow through a fine space between the tapering portion 24 and the conical portion of the through-bore 22. The position of the threaded body 25 may be axially adjusted so that the size of the fine space, that defines an air flow passage, may be adjusted.

It is to be appreciated that whilst one type of air bleed valve has been described, many alternative types of air bleed valve may be useful in embodiments of the invention.

The piston is illustrated, in Figures 1 and 2, in an initial position in which the toilet seat is upright. The piston is located towards the closed end of the bore 16 defined in the upstanding plate 15.

The toilet seat may be adapted to be lowered, automatically, to a lower position, with the toilet seat moving under the force of gravity, but against a generally upward bias provided by the spring 8. The spring 8 may simply be adapted to be compressed as the toilet seat is lowered, as the nut 9 moves towards the arm 4, as will now be described, or the spring may provide a "torsion" effect, being secured to the shaft.

7 As the toilet seat moves towards the closed position, the shaft 5 will rotate. Rotation of the shaft 5 will cause the nut 9 to move axially relative to the shaft, since the nut cannot rotate due to the engagement of the depending lug 10 within the channel 11. As the nut moves relative to the shaft, so the nut applies an axial force to the piston 14, serving to withdraw the piston:firom the bore 16. As the piston moves within the bore, so air is drawn, through the airbleed valve 17 into the chamber defined within the bore between the piston 14 and the closed end of the bore. Since air has to be drawn into the chamber through the bleed-valve 17, the speed at which the nut 9 may move is regulated, and thus the speed of rotation of the shaft 5 is regulated, and consequently the described apparatus provides a desired governing effect. The toilet seat may thus move slowly and evenly towards the lowered position.

Turning now to Figure 7, a modified embodiment of the invention is illustrated. However, in this embodiment the upstanding plate 18 defines a bore 30 which is of increased length as compared with the bore 16. Partway along the length of the bore 30 is an air-passage 31 communicating from the exterior of the upstanding plate 18 to the interior of the bore.

It is to be appreciated that in utilising an embodiment of the type illustrated in Figure 7, the bleed-valve 17 may be adjusted to permit only a very slow rate of flow of air into the bore 30. Thus the piston 14 will only be able to move very slowly during an initial part of the movement of the piston. However, once the piston has moved past the transverse air-passage 3 1, air will be able to flow into the region of the bore 30 that communicates with the airbleed valve 17 through the passage 3 1, and consequently the piston 14 may then move to the left with an increased velocity.

8 Thus in an embodiment incorporating a unit of the type shown in Figure 7, the toilet seat may move slowly for a period of time until the piston has reached the air-passage 3 1, and the piston may then move more swiftly, although the relatively swift movement will still be governed by the speed at which air may be drawn into the bore 3 0 through the air inlet 3 1. Thus this arrangement provides, effectively, a timing mechanism, with the seat only moving very slightly during the first period of time, and subsequently moving to the closed position more swiftly.

Figure 8 illustrates a modified embodiment of the invention which is very similar to the embodiment described above with reference to Figures 1 to 4, but the nut 9 has been replaced by a follower 40 which surrounds the shaft 5, and which is provided with a slit 41 which extends in such a way that the slit 41 is inclined relative to the axis of the shaft 5. The slit 41 is engaged by a radially outwardly extending projection 42 which extends outwardly firom the shaft 5. The projection 42 is in the form of a rod having a diameter which is substantially equal to the width of the slit 41. Thus, as the shaft 5 rotates, the rod, or projection 42, is constrained to move along the slit 41. The rod engages one of the two side faces of the slit 4 1, and thus causes the follower 40 to move axially in response to rotational movement of the shaft 5. It can be seen that the described follower, and the co-operating projection 42 operate in the same way as the thread and nut arrangement described above, with particular reference to Figures 1 to 3.

The remaining features of the apparatus shown in Figure 8 correspond directly with the remaining features of the apparatus shown in Figure 1, and will thus not be re-described.

9 In the present specification "comprise" means 'Includes or consists of' and "comprising" means 'Including or consisting of'.

The features disclosed in the foregoing description, or the following claims, or the accompanying drawings, expressed in their specific forms or in terms of a means for perforniing the disclosed function, or a method or process for attaining the disclosed result, as appropriate, may, separately, or in any combination of such features, be utilised for realising the invention in diverse forms thereof.

Claims

CLAIMS:

1. A governor adapted to govern the speed of rotation of a shaft, the shaft being provided with a portion having an external projection, a follower being provided adapted to engage the external projection of the shaft, the projection or the follower presenting an inclined face inclined relative to the axis of the shaft, means being provided to constrain the follower to permit the follower to move axially whilst preventing the follower from rotating, the follower being connected to means which define part of a chamber, so that rotation of the shaft moves the follower which consequently moves the said means defining part of a chamber to alter the volume of the chamber, means being provided defining a restricted air-flow passage communicating with the interior of the chamber.

2. A governor according to Claim 1 wherein the external projection comprises a helical thread and the follower is a nut.

A governor according to Claim 1 wherein the follower surrounds the shaft and defines a slot, engaged by the projection, which slot is inclined relative to the axis of the shaft.

4. A governor according to any one of the preceding Claims wherein the means defining a restricted air-flow passage to the interior of the chamber comprise an adjustable air bleed valve.

5. A governor according to Claim 4 wherein the adjustable air bleed valve comprises a passage incorporating a conical tapering section and a flow regulating element inserted into said passage, the flow regulating element 11 having a conical tapering portion within the conical tapering portion of the passage to define a relatively narrow, but adjustable, air-flow space therebetween.

6. A governor according to any one of the Claims 1 to 4 wherein the means defining a chaniber comprise a piston which is contained within a bore, the bore having a closed end, the chamber being defined between the piston and the closed end of the bore.

7. A governor according to Claim 6 wherein said restricted air-flow passage is provided communicating with the closed end of the bore, and a supplementary air-flow passage, of greater diameter than the restricted air-flow passage, is provided communicating with part of the bore which is spaced from the closed end of the bore.

8. A governor according to any one of the proceeding Claims incorporated in a toilet seat.

9. A governor substantially as herein described with reference to and as shown in Figures 1 to 6 of the accompanying drawings.

10. A governor substantially as herein described with reference to and as shown in Figures 1 to 6 of the accompanying drawings as modified by Figure 7.

11. A governor substantially as herein described with reference to and as shown in Figures 1 to 6 of the accompanying drawings as modified by Figure 8.

12. Any novel feature or combination of features disclosed herein.