GB2042651A

GB2042651A - Plummer Block

Info

Publication number: GB2042651A
Application number: GB8000997A
Authority: GB
Original assignee: SKF AB
Current assignee: SKF AB
Priority date: 1979-01-11
Filing date: 1980-01-11
Publication date: 1980-09-24
Also published as: FR2446409B3; JPS5597525A; IT1127748B; IT7928402A0; DE3000391A1; IT7923480V0; SE7900264L; FR2446409A1

Abstract

The invention relates to a plummer block made from steel plate. To decrease the rigidity of the block, grooves (6) are cut in the stiff stays (2). In addition to the grooves (6) holes (7) have been made in the central part (1) of the block to give this part the desired flexibility. <IMAGE>

Description

SPECIFICATION Plummer Block The present invention relates to a plummer block made of pressed metal for spherical bearings. Such plummer blocks are usually cheap to manufacture, and they are preferably used in simple applications.

When a shaft is to be carried by bearings, usually two bearings are mounted on the shaft at a distance from each other and are mounted each in a separate housing. The primary requirements of the housings are that they shall have sufficient strength to carry the shaft in a reliable way, and also be so rigid that the shaft is not displaced either radially or axially. However, temperature variations, vibrations and the iike will always occur, causing the length of the shaft to vary. If the shaft has been rigidly mounted between two housings, strong forces will then act on the bearings due to these length variations.

Sometimes the position of the housing may also be changed, for example by loads acting on the frame or foundation on which it has been mounted. Also then the bearing will be subjected to strong axial forces if the plummer block is rigid.

Axial forces on a spherical bearing decreases appreciably the life. It is, consequently, a desire, that one of the bearings shall be mounted somewhat less r rigidly or somewhat movably in an axial direction, so that stresses do not occur.

in one aspect the invention provides a plummer block made of pressed metal for spherical rolling bearings comprising a central portion having one or more stay portions protrudiftgatan angle from the central portion, characterised in that the stay portion and possibly the central portion are provided with a cutting groove or have been cut and that in the central portion possibly an aperture has been made, in which the cut shall end so that the plummer block is turnable around a torsion line between the mounting points.

In another aspect the invention provides a pressed sheet metal plummer block comprising a base, a frame having a bearing seat, and at least one stay, the frame having an aperture and/or the stay having a slit providing the plummer block with a torsion line about which the plummer block can be repeatedly turned, the bearing seat axis lying in a plane perpendicular to the torsion line.

An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, of which: Figure 1 is a perspective of a plummer block of the prior art; Figure 2 is a perspective of a plummer block according to the invention; Figure 3 is a side view of the plummer block according to the invention and including a bearing; and Figure 4 is a diagram comparing the resiliency of the plummer blocks.

The plummer block according to Figure 1 consists of two halves having a central portion 1 and two stay portions 2. The pressed halves are identical and assembled by means of rivets or the like 3. The annular portion carrying the bearing has been denoted with 4. Foot plates 5 have been made for common mounting of the plate halves in a frame. The construction shown is very reliable but it has the feature that it, in many applications, is far too rigid.

In order to reduce the rigidity the stay portions 2 are provided with cutting grooves 6 and apertures 7 provided in the central portion 1. As appears the cutting grooves will end in the apertures 7. These apertures 7 do not weaken the plummer block itself. It is therefore possible to make the plummer block at each end of the shaft identical and with the apertures 7, and when mounting, cut one of the plummer blocks along the cutting grooves 6.

It is accordingly possible to produce all the four identical plummer block halves with one single tool. If a large number of plummer blocks are to be produced, it can, of course, be advantageous to cut the stay portions directly in the factory, so that this work does not have to be done by the assembler.

If an axial load P is put on the plummer block this will, after the cutting, make a movement having a torsion line 8. This movement around the line 8 will be a torsional movement and not a simple bending movement. Therefore, the plummer block may be turned around this line 8 an indefinite number of times, whereas a simple bending movement of the plate would rapidly destroy the plate. The ability of the plummer block to take up radial forces is practically unchanged.

Figure 3 is a side view of a plummer block according to the invention and including a bearing and for different forces P the movement A at the upper part of the plummer block has been measured. The line C in Figure 4 shows how large this movement is in millimeters measured for different magnitudes of the force P. For comparison the curve D has been included. It shows the same measurements for a plummer block which has not been cut. As is apparent, a vast difference in the resiliency of the plummer block has been obtained.

Claims

1. A plummer block made of pressed metal for spherical rolling bearings comprising a central portion having one or more stay portions protruding at an angle from the central portion, characterized in that the stay portion but possibly the central portion are provided with a cutting groove or have been cut and that in the central portion possibly an aperture has been made, in which the cut shall end so that the plummer block is turnable around a torsion line between the mounting points.

2. A plummer block according to claim 1, characterised in that it consists of two identical and axially assembled halves.

3. A pressed sheet metal plummer block comprising a base, a frame having a bearing seat,

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. SPECIFICATION Plummer Block The present invention relates to a plummer block made of pressed metal for spherical bearings. Such plummer blocks are usually cheap to manufacture, and they are preferably used in simple applications. When a shaft is to be carried by bearings, usually two bearings are mounted on the shaft at a distance from each other and are mounted each in a separate housing. The primary requirements of the housings are that they shall have sufficient strength to carry the shaft in a reliable way, and also be so rigid that the shaft is not displaced either radially or axially. However, temperature variations, vibrations and the iike will always occur, causing the length of the shaft to vary. If the shaft has been rigidly mounted between two housings, strong forces will then act on the bearings due to these length variations. Sometimes the position of the housing may also be changed, for example by loads acting on the frame or foundation on which it has been mounted. Also then the bearing will be subjected to strong axial forces if the plummer block is rigid. Axial forces on a spherical bearing decreases appreciably the life. It is, consequently, a desire, that one of the bearings shall be mounted somewhat less r rigidly or somewhat movably in an axial direction, so that stresses do not occur. in one aspect the invention provides a plummer block made of pressed metal for spherical rolling bearings comprising a central portion having one or more stay portions protrudiftgatan angle from the central portion, characterised in that the stay portion and possibly the central portion are provided with a cutting groove or have been cut and that in the central portion possibly an aperture has been made, in which the cut shall end so that the plummer block is turnable around a torsion line between the mounting points. In another aspect the invention provides a pressed sheet metal plummer block comprising a base, a frame having a bearing seat, and at least one stay, the frame having an aperture and/or the stay having a slit providing the plummer block with a torsion line about which the plummer block can be repeatedly turned, the bearing seat axis lying in a plane perpendicular to the torsion line. An embodiment of the invention will now be described by way of example and with reference to the accompanying drawings, of which: Figure 1 is a perspective of a plummer block of the prior art; Figure 2 is a perspective of a plummer block according to the invention; Figure 3 is a side view of the plummer block according to the invention and including a bearing; and Figure 4 is a diagram comparing the resiliency of the plummer blocks. The plummer block according to Figure 1 consists of two halves having a central portion 1 and two stay portions 2. The pressed halves are identical and assembled by means of rivets or the like 3. The annular portion carrying the bearing has been denoted with 4. Foot plates 5 have been made for common mounting of the plate halves in a frame. The construction shown is very reliable but it has the feature that it, in many applications, is far too rigid. In order to reduce the rigidity the stay portions 2 are provided with cutting grooves 6 and apertures 7 provided in the central portion 1. As appears the cutting grooves will end in the apertures 7. These apertures 7 do not weaken the plummer block itself. It is therefore possible to make the plummer block at each end of the shaft identical and with the apertures 7, and when mounting, cut one of the plummer blocks along the cutting grooves 6. It is accordingly possible to produce all the four identical plummer block halves with one single tool. If a large number of plummer blocks are to be produced, it can, of course, be advantageous to cut the stay portions directly in the factory, so that this work does not have to be done by the assembler. If an axial load P is put on the plummer block this will, after the cutting, make a movement having a torsion line 8. This movement around the line 8 will be a torsional movement and not a simple bending movement. Therefore, the plummer block may be turned around this line 8 an indefinite number of times, whereas a simple bending movement of the plate would rapidly destroy the plate. The ability of the plummer block to take up radial forces is practically unchanged. Figure 3 is a side view of a plummer block according to the invention and including a bearing and for different forces P the movement A at the upper part of the plummer block has been measured. The line C in Figure 4 shows how large this movement is in millimeters measured for different magnitudes of the force P. For comparison the curve D has been included. It shows the same measurements for a plummer block which has not been cut. As is apparent, a vast difference in the resiliency of the plummer block has been obtained. Claims

3. A pressed sheet metal plummer block comprising a base, a frame having a bearing seat, and at least one stay, the frame having an aperture and/or the stay having a slit providing the plummer block with a torsion line about which the plummer block can be repeatedly turned, the bearing seat axis lying in the plane perpendicular to the torsion line.

4. A plummer block as claimed in claim 1, wherein the block is formed from two identical axially opposed halves.

5. A plummer block substantially as herein described with reference to and as shown in Figures 2,3 and 4 of the accompanying drawings.