Roller for belt conveyor

The head (11) (40) of a belt conveyor roller is press-fit into a cylindric shell (10) of the roller. The head (11) (40) defines a bearing chamber (12) for a frictionless bearing (14-15; 42) which is closed by a ring assembly (21, 29) welded to the head and provided, in the embodiment disclosed, with a stainless steel lamella (33, 59) the opening (60) of which bites into the resilient outer cylindric surface (61) of a hub section (28, 53), to provide a virtually hermetical enclosure of the bearing chamber (12, 41) thus increasing the safety of the operation by isolating the possible point of ignition or explosion on seizure of the bearing (14-15; 41) of the roller. The roller equipped with the assembly of the present invention thus presents a further improvement in the art of belt conveyors for use in hazardous environments.

I claim:

1. A roller for use in belt conveyor including a hollow cylindric shell and two end assemblies, one at each end of the shell, the assemblies being generally a mirror image of each other, each end assembly comprising, in combination:

(a) a generally cylindric head coaxial with said shell and fixedly and hermetically secured to same;

(b) said head defining a bearing chamber; an antifriction bearing mounted in the bearing chamber for rotatably supporting the roller on an axle, said head further defining a generally cylindric seal chamber disposed axially outwardly of and coaxial with said bearing chamber;

(c) a seal assembly disposed in said seal chamber and comprising:

(1) a bush portion with a radially inwardly directed flange, said bush portion being made of a thermoplastic material and having an axially inner face abutting against an outer ring of said antifriction bearing, the other, axially outer face of the bush portion being hermetically secured to an outer face portion of said head;

(2) a hub portion with a radially outwardly directed flange, an inner axial face of said hub portion abutting against an inner ring of said antifriction bearing, said hub portion including a generally cylindric sleeve section, a part of said sleeve section projecting axially out of the head, said sleeve section being press fit mounted on the respective axle and including a lamella engaging surface part which has a first predetermined resiliency; and

(3) seal means disposed between said flanges, said bush portion and said sleeve section;

(d) an annular front cover lamella made of a material having a second predetermined resiliency which is substantially different from the first predetermined resiliency, and having an opening; the difference between the predetermined resiliencies and the size of said opening of the lamella being suitable to allow an overlapping but mutually rotational engagement between the lamella and said lamella engaging surface part of the hub section;

(e) an annular securement member placed over an outer face of said lamella and holding same in axial engagement with the axially outer face of the bush portion; and

(f) locking means for interlocking said lamella and the head for a synchronous rotation.

2. A roller as claimed in claim 1, wherein said locking means is a plurality of axial passages in said lamella and a plurality of compatible locking stems projecting inwardly from said securement member through said passages into correspondingly shaped recesses in the head, whereby both the lamella and the securement member are locked for said synchronous rotation.

3. A roller as claimed in claim 1, wherein the seal means is a soft annular seal.

4. A roller as claimed in claim 3, wherein the soft annular seal is a felt seal.

5. A roller as claimed in one of claims 3, wherein one of said flanges is provided with locking projections penetrating an adjacent face of said seal.

6. A roller as claimed in one of claims 3, wherein said outwardly directed flange is provided with locking projections adapted to penetrate an adjacent face of said seal for securement of a synchronous rotation of the seal with the second flange portion.

7. A roller as claimed in claim 1, wherein said inwardly directed flange and said outwardly directed flange are provided with complementary axial projections defining a labyrinth seal therebetween.

8. A roller as claimed in claim 7, wherein said bush portion is comprised of an axially inner subsection abutting against said outer ring of the bearing, and an axially outer subsection fixedly secured to the casing and to the axially inner subsection, said axially outer subsection including an axially outward, second radially inwardly directed end wall flush with said lamella and defining, with the outwardly directed second flange portion, a second seal chamber housing a soft seal ring, whereby the seal assembly comprises a labyrinth seal and a soft annular seal, the two seals being disposed one to each axial side of said outwardly directed flange.

9. A roller as claimed in claim 8, wherein the hermetic securement of said bush portion to the casing is made by welding said axially outer section to the casing.

10. A roller as claimed in claim 1, wherein the hermetic securement of said bush portion to the casing is made by welding the thermoplastic material of the bush portion to the head.

11. An end assembly for use in a belt conveyor roller, which roller includes a hollow cylindric shell and two end assemblies, one at each end of the shell, the assemblies being generally a mirror image of each other, each end assembly comprising, in combination:

(a) a generally cylindric head compatible with said shell for becoming fixedly, coaxially and hermetically secured to same;

(b) said head defining a bearing chamber adapted to receive an antifriction bearing for rotatably supporting a respective roller on an axle, said head further defining a generally cylindric seal chamber adapted to be disposed, upon assembly, axially outwardly of and coaxial with said bearing chamber;

(c) a seal assembly adapted to become disposed in said seal chamber and comprising:

(1) a bush portion with a radially inwardly directed flange, said bush portion being made of a thermoplastic material and having an axially inner face adapted to abut against an outer ring of a respective antifriction bearing, the other, axially outer face of the bush portion being adapted to become hermetically secured to an outer face portion of said head;

(2) a hub portion with a radially outwardly directed flange, an inner axial face of said hub portion being adapted to abut, upon assembly, against an inner ring of said respective antifriction bearing, said hub portion including a generally cylindric sleeve section, a part of said sleeve section beind adapted to project, upon assembly, axially out of the head, said sleeve section being dimensioned for a press fit on a respective axle and including a lamella engaging surface part which has a first predetermined resiliency; and

(3) seal means adapted to become disposed between said flanges, said bush portion and said sleeve section;

(d) an annular front cover lamella made of a material having a second predetermined resiliency which is substantially different from the first predetermined resiliency, and having an opening; the difference between the predetermined resiliencies and the size of said opening of the lamella being suitable to allow an overlapping but mutually rotational engagement between the lamella and said lamella engaging surface part of the hub section;

(e) an annular securement member adapted to be placed over an outer face of said lamella to holding same in axial engagement with the axially outer face of the respective bush portion; and

(f) locking means for interlocking said lamella and the head for a synchronous rotation.