GB2209578A

GB2209578A - A connection

Info

Publication number: GB2209578A
Application number: GB8720908A
Authority: GB
Inventors: David Colston Beauchamp
Original assignee: HATTERSLEY HEATON Ltd
Current assignee: HATTERSLEY HEATON Ltd
Priority date: 1987-09-05
Filing date: 1987-09-05
Publication date: 1989-05-17
Anticipated expiration: 2007-09-05
Also published as: GB8720908D0; GB2209578B

Abstract

A connection between two members, for example, the shaft 3 and disc 2 of a butterfly valve comprises keyways in each member. These are aligned to permit insertion of a key 6 which has a portion 10 of reduced height. After insertion the members are moved relatively axially one inside the other. The key is entrained by that one member and located inside the other to lock the two members together. This provides an efficient readily disassemblable connection between the members. <IMAGE>

Description

A CONNECTION The present invention relates to a connection between members. It is particularly, but not exclusively applicable to the connection between the valve member and shaft in a butterfly valve.

Many such butterfly valves are designed with shaft to valve member connection via pins inserted in holes passing through both member and shaft. The problem associated with this design is related to the initial operation of the disc in and out the seat which creates very high stresses on the pins, which wear and which can eventually shear.

According to the present invention there is provided a connection between members one of which extends through the other in which each member is formed with a keyway which can be aligned to enable. insertion of a key and then disaligned to entrain the key with the inner member inside the other member whereby to lock the key in the member to connect the two members together.

In a preferred embodiment of the invention, the two members are the shaft and disc form valve member of a butterfly valve. The keyway in the shaft is shorter than that in the valve member and equal to the length of the key. The key has a portion of reduced height and the height of this portion is equal to the depth of the keyway in the shaft. The keyway in the valve member is longer than that in the shaft and the sum of the depths of both keyways is equal to the height of the key. The key has a slot in it to enable it to be levered out of the keyways when the keyways are aligned for example with the aid of a screwdriver. The shaft is stepped at one end to limit the disalignment of the keyways by movement of the shaft in the valve member and an end plate is provided to hold the shaft in this position relative to the valve member and prevent access to the end of the shaft.

In order that the present invention may be more clearly understood, one embodiment thereof will now be described, by way of example, with reference to the accompanying drawings in which: Figure 1 shows a side elevational view in section of a butterfly valve partly assembled in accordance with the invention, and Figure 2 shows the valve of Figure 1 fully assembled.

Referring to the drawings, the butterfly valve comprises a valve body 1 in which a disc form valve member 2 is rotatably mounted on a shaft 3. The shaft 3 extends through bores in the body 1 and member 2. The shaft has a stepped portion 4 at its upper end which locates in a complementary formed portion 5 of the bore in the valve body. The valve member 2 and shaft 3 are connected together by means of a key 6. This key 6 and the slots in the member 2 and shaft 3 into which it is inserted are specially formed to enable the connection of the member 2 and shaft 3 together. The slot in the shaft 3 is referenced 7 and that in the member 2 is referenced 8.

The key 6 which is oblong and of constant thickness has a height that corresponds to the depth of the open slot 8 in the member 2 plus the depth of the slot 7 in the shaft 3. One third of the key length is reduced in height at 10 to the corresponding height of the slot in the shaft. A screwdriver slot 9 is produced in the end of key 6 that has the full width. The keyway slot 7 is produced to the exact length of the key 6 and to an exact depth of the reduced one third key height. That keyway slot 8 produced in the back of the member 2 extends through to the hole bored for the shaft 3. The length of the slot 8 is approximately one third longer than the key length.

The valve is assembled in the following manner. The disc form member 2 is located in the valve body 1. The shaft 3 is passed through the bottom bore of body 1 into the bore through member until the shaft keyway slot 7 is visible through the member keyway slot 8. The key 6 is inserted into the member 2 into disc and shaft slots with the reduced height portion 10 of the key facing in the direction of the-shaft's final assembly position. After inserting the key 6 the shaft 3 is pushed upwards into its final position. Entraining the key up into the member inside diameter until the stepped portion 10 of the key 6 comes into contact with the end of the slot 8 in the disc member 2. The bottom end of the shaft 3 is held with a shaft retainer 11, preventing axial movement of the shaft 3, and locking the key 6 in position. In order to disassemble the shaft 3 and member 2 the shaft retainer 11 is first removed. The shaft 3 is then pushed down until key 6 is visible in keyway slot 8 exposing the screwdriver slot 9 at the bottom end of key 6. By inserting an instrument in the slot 9 the key may be levered out of both the shaft and disc member slot 7 and 8. The shaft 3 can now be removed through the bottom hole in the valve body.

It will be appreciated that the above embodiment has been described by way of example only and that many variations are possible without departing from the invention.

Claims

1. A connection between members one of which extends through the other in which each member is formed with a keyway which can be aligned to enable insertion of a key and then disaligned to entrain the key with the inner member inside the other member whereby to lock the key in the member to connect the two members together.

2. A connection as claimed in claim 1, in which the keyway in the said one member is shorter than that in the other member.

3. A connection as claimed in claim 1 or 2, in which the key has a portion of reduced height and this height is equal to the depth of the keyway in the said one member.

4. A connection as claimed in claim 1, 2 or 3, in which the keyway in the other member is longer than that in the said one member and the sum of the depths of both keyways is equal to the height of the key.

5. A connection as claimed in any preceding claim, in which the key defines a slot to enable it to be levered out of the keyways when they are aligned.

6. A connection as claimed in any preceding claim, in which the said one member is stepped at one end to limit disalignment of the keyways by relative movement of the members and an end plate is provided to hold the members in relative position and prevent access to that end of the said one member.

7. A connection as claimed in any preceding claim, in which the said one member is the shaft and the other member is the disc form valve closure member of a butterfly valve.

8. A connection between members substantially as hereinbefore described with reference to the accompanying drawings.