FIELD OF INVENTION This invention relates to conveyor belt rollers and, in particular, to an impact absorbing idler roller for supporting a conveyor belt at a load transfer point, for example. More particularly, the present invention relates to an impact absorbing roller wall or bearing housing which has been designed, constructed and arranged to have improved impact or shock absorption characteristics.

BACKGROUND OF INVENTION

Impact or shock absorption is a necessity at a load transfer point in order to prevent damage to the conveyor belt as well as damage to roller bearings and shafts. An existing impact absorbing roller used to support a conveyor belt at a load transfer point, or at any other point along a length of the belt where there is a need for shock absorption, includes a plurality of polymeric discs which are concentrically mounted to a hub for rotation about an idler shaft. The discs may be axially spaced apart. The discs are supposedly configured to absorb shock transferred to it by the belt when load is applied to the belt. Consequently, in order to give rise to an impact absorbing effect, the discs have to be at least partially resilient. The Applicants are of the view that these prior art impact absorbing rollers in fact have very little yield which means that a lot of the force is applied directly to the conveyor belt itself which damages the conveyor belt over time. Furthermore, due to a lack of yield in the rollers the force applied to the discs is directly transferred to the shaft and bearings. In an alternative embodiment of the impact absorbing roller, a continuous outer tube or cylinder made from polymeric material may be provided over the hub, the cylinder being configured to absorb shock applied to the belt.

There are drawbacks associated with these types of prior art impact absorbing rollers. First, they are expensive because a large volume of polymeric material is used to construct the discs or polymeric cylinders. Most steel rollers are hollow which means less material is required, but these prior art impact absorbing rollers have solid polymeric outer shells made up of the plurality of discs. Accordingly, the polymeric material extends for an entire length of the roller. The discs are typically made from either rubber or polyurethane. Rubber is cheaper than polyurethane. However, natural rubber poses a fire hazard. In the event that the bearings of the rubber impact absorbing roller cease, friction caused by movement of the conveyor belt over the stationary discs of the roller could cause a fire. The discs may be treated with a fire retardant, but this proves to be prohibitively expensive especially because multiple discs are used on each roller which means there is a large volume or surface area of rubber which needs to be treated. Furthermore, the fire retardant hardens the rubber to such a degree that it becomes even less useful as an impact dampener. Producing a Fire Retardant Anti-Static (FRAS) rated roller may drive the cost of manufacturing up considerably. In the case of a roller having polyurethane walls, the cost of producing a FRAS rated roller may be ±400% more expensive. Regulatory compliance may require that each disc of the roller be FRAS rated. In specific applications, polyurethane has better structural integrity and stability than rubber, but it is more expensive.

An increased surface area caused by the plurality of axially spaced discs may also result in less deflection or yield of individual discs because the load is spread out across the discs collectively. Lack of adequate shock absorption or yield by the discs when subjected to a force may result in greater strain being transferred to the bearings which effectively reduce their operational lifespan. This lack of sufficient resilient adsorption defeats the purpose of an impact absorbing roller because it does not dampen the impact shock applied to the conveyor belt, which is the most expensive part of a conveyor. The Applicants are aware of other rollers that have vibration absorbing bearing carriers or bearing housings, but these are not suitable for the purposes of impact or shock absorption at load transfer points due to their insufficient or inadequate shock absorption ability. These bearing carriers or bearing housings allow minimal yield or movement between the shaft and the roller shell making it an unsuitable option for use at transfer points. Furthermore, typically these bearing carriers are made of fairly hard, inelastic material such as Nylon or High-density Polyethylene (HDPE) which does not have sufficient give or yield to support or absorb large impact loads. Polyurethane bearing carriers have also been used but these are too stiff, i.e. lack adequate resilience which means they are not suitable for use at transfer points due to their inability to yield adequately. Their inability to yield adequately may also be due to their small diameter.

It is an object of the invention to provide an idler roller and an impact absorbing roller wall with an integral bearing housing which address, at least to some extent, the abovementioned drawbacks. SUMMARY OF INVENTION

In accordance with a first aspect of the invention, there is provided an impact absorbing roller wall for an idler roller which is configured to support a conveyor belt, the idler roller including an idler shaft defining a longitudinal shaft axis and a tubular outer shell defining a central shell axis, wherein the impact absorbing roller wall extends between the idler shaft and the tubular outer shell and defines a central bore for accommodating the idler shaft, the impact absorbing roller wall being configured to support the tubular outer shell for rotation about a rotation axis, the impact absorbing roller wall including: a bearing housing which defines a bearing seat for receiving a bearing for facilitating rotation of the impact absorbing roller wall about the rotation axis; and

a shock absorbing zone which extends from the bearing housing to an outer periphery of the impact absorbing roller wall, wherein the tubular outer shell has a radius R and wherein the impact absorbing roller wall is resiliently deformable operatively to permit displacement of the tubular outer shell relative to the idler shaft by a displacement distance ranging from between 0.015 ^* R and 0.4 ^* R in response to a load being applied to the tubular outer shell.

The displacement distance may range from between 0.03 ^* R and 0.25 ^* R. More specifically, the displacement distance may range from between 0.05 ^* R and 0.1 ^* R.

The shock absorbing zone may have an inclination which extends radially inward from the outer periphery of the roller wall toward the bearing housing. The inclination of the shock absorbing zone may extend radially and axially inward from the outer periphery of the roller wall toward the bearing housing. Accordingly, the shock absorbing zone may include an axially inwardly slanted annular wall which is configured to limit axial movement of the idler shaft relative to the tubular outer shell.

The bearing housing may be integrally formed with the shock absorbing zone. The roller wall may include a circumferentially extending lip which is configured to mate with the tubular outer shell. The roller wall may be made from polymeric material and may be resiliently deformable in a radially inward direction. The roller wall may be made from polyurethane having a hardness which results in durometer readings ranging between 55 and 95 based on the Shore hardness test. The roller wall may be annular and disc-shaped. The bearing seat may be radially inwardly disposed and may face axially inward. The roller wall may be treated with a fire retardant and may have anti-static characteristics.

In accordance with another aspect of the invention, there is provided an idler roller for supporting a conveyor belt at a load transfer point, the idler roller including: a tubular outer shell; and

at least one impact absorbing roller wall as described above which operatively supports the tubular outer shell and extends radially inward and defines a central bore for accommodating an idler shaft, wherein the impact absorbing roller wall is resiliently deformable in response to a load being applied to the tubular outer shell.

The idler roller may include at least two longitudinally spaced apart impact absorbing roller walls, one at each end of the tubular outer shell.

The idler roller may be an impact absorbing idler roller which includes a bearing assembly which is operatively received within the bearing housing of the impact absorbing roller wall. The bearing assembly may be configured rotatably to support the impact absorbing roller walls and tubular outer shell for rotation about the rotation axis. The bearing assembly may include an engineering felt seal which is received within the bearing housing.

The tubular outer shell may be rigid. The tubular outer shell may be made from metal. The idler shaft may be rigid and hollow. The idler shaft may have a machined journal at each end for receiving a bearing.

The idler roller may include a circumferentially extending locating groove formed in the tubular outer shell, proximate ends of the shell, for locating the impact absorbing roller walls relative to the tubular outer shell and securing the roller walls to the tubular outer shell by way of an interference fit.

The idler roller may include at least two axially spaced apart tubular outer shells which are mounted to the same idler shaft by way of respective pairs of impact absorbing roller walls such that the tubular outer shells are independently resiliently displaceable relative to the idler shaft when subjected to loads. In accordance with another aspect of the invention, there is provided a method of constructing an idler roller for supporting a conveyor belt at a load transfer point, the method including:

providing an elongate idler shaft having a journal for receiving a bearing at either end;

seating a bearing in a bearing seat of an impact absorbing roller wall as described above and positioning the roller wall over the journal such that an end of the idler shaft protrudes through a central bore of the roller wall;

sliding a tubular outer shell over a distal free end of the idler shaft and partially inserting the impact absorbing roller wall into an open end of the tubular outer shell; and

partially inserting a second impact absorbing roller wall including a bearing into an opposing open end of the tubular outer shell by sliding the roller wall over the journal of the idler shaft.

The method may include crimping ends of the tubular outer shell over an outer periphery of the respective roller walls to secure the roller walls in place.

The method may include the prior step of rolling a circumferentially extending groove into the tubular outer shell, proximate ends thereof, for locating the roller walls with respect to the tubular outer shell.

The roller wall may be treated with a fire retardant. The roller wall may be impregnated or doped with the fire retardant. The fire retardant may be applied to the roller wall. The roller wall may have anti-static characteristics.

The roller wall may be injection moulded. The roller wall may also be cast. The roller wall may be in abutment with the outer shell. Consequently, the roller wall may extend from the idler shaft to the outer shell.

The bearing assembly may be configured to facilitate rotation of the shell and roller wall about the rotation axis. The bearing assembly may include a graphite seal/engineering felt seal. The bearing itself may serve as a chrome/graphite seal at a radially outward position with respect to the inner graphite seal. The roller wall may serve as a shock absorber. Accordingly, the roller wall may be shaped to absorb impact.

The idler roller may also find application at areas where suspension would be of benefit such as where the conveyor belt changes angle which places a greater force on the rollers.

The shock absorbing zone may be resiliently deformable in response to a load being applied to the tubular outer shell by way of elastic compression of a load bearing side of the roller wall and elastic extension of an opposing side of the roller wall to permit relative displacement of the idler shaft and tubular outer shell. The shock absorbing zone may be configured to compress concertina fashion.

The impact absorbing roller wall may have an annular bearing housing which is configured to rotate about the bearing seated within the bearing seat, when subjected to adequate load, despite that the bearing has ceased.

BRIEF DESCRIPTION OF DRAWINGS The invention will now be further described, by way of example, with reference to the accompanying diagrammatic drawings.

In the drawings:

Figure 1 shows a three-dimensional assembled view of a first embodiment of an impact absorbing idler roller in accordance with the invention;

Figure 2 shows a side view of the roller of Figure 1 with dotted lines indicating a position of an outer shell when a load is applied to the roller; Figure 3 shows a longitudinal section of the roller shown in Figure 2, taken along lines B-B;

Figure 4 shows a three-dimensional exploded view of the roller of Figure 1 ; and

Figure 5 shows a longitudinal section through part of a second embodiment of an impact absorbing idler roller;

Figure 6 shows a three-dimensional view of a third embodiment of the impact absorbing idler roller in accordance with the invention;

Figure 7 shows an exploded three-dimensional view of the idler roller of Figure 6;

Figure 8 shows a longitudinal section through the idler roller of Figure 6 in an operative condition;

Figure 9 shows another longitudinal section through the idler roller of Figure 6 when subjected to normal loading;

Figure 10 shows another longitudinal section through the idler roller of

Figure 6 when subjected to maximum loading;

Figure 1 1 shows a further longitudinal section through the idler roller of Figure 6 when subjected to uneven loading;

Figure 12 shows another longitudinal section through a fourth embodiment of the impact absorbing idler roller in accordance with the invention; and

Figure 13 illustrates an exploded sectional view of a bearing assembly of the idler roller of Figure 12. DETAILED DESCRIPTION OF AN EXAMPLE EMBODIMENT

The following description of the invention is provided as an enabling teaching of the invention. Those skilled in the relevant art will recognise that many changes can be made to the embodiments described, while still attaining the beneficial results of the present invention. It will also be apparent that some of the desired benefits of the present invention can be attained by selecting some of the features of the present invention without utilising other features. Accordingly, those skilled in the art will recognise that modifications and adaptations to the present invention are possible and can even be desirable in certain circumstances, and are a part of the present invention. Thus, the following description is provided as illustrative of the principles of the present invention and not a limitation thereof. In figures 1 to 4, reference numeral 10 refers generally to a first embodiment of an impact absorbing idler roller, in accordance with the invention, for supporting a conveyor belt at a load transfer point. The roller 10 includes a roller body which includes a tubular outer shell or drum 12, and a pair of resiliently deformable roller walls 13 which are connected to opposing ends of the shell 12 and operatively support the shell 12. The roller walls 13, which may also be referred to as end walls, extend radially inwardly and define a central bore 15 for accommodating an idler shaft 16 (see figure 4). The shell 12 and roller walls 13 are mounted to the idler shaft 16 for rotation about a rotation axis X by a pair of bearing assemblies mounted to journals of the idler shaft 16 toward opposing end regions 17 of the shaft 16. The shell 12 and roller walls 13 are therefore rotatably mounted to the shaft 16. The tubular outer shell 12 has a radius R1 (see figure 2).

Each roller wall 13 has a circular or annular, inner bearing housing 18 which is integrally formed with a remainder of the roller wall 13. The bearing housing 18 operatively protrudes inwardly in an axial direction. The roller wall 13 further includes a circumferentially extending outer lip 19 and a shock absorbing zone 20 extending between the bearing housing 18 and outer lip 19. A cross-sectional profile of the shock absorbing zone 20 may take on different shapes in order to improve its ability to absorb shock. The bearing housing 18 defines an axially inwardly facing bearing seat 21 for receiving a bearing 22 of one of the bearing assemblies by way of a friction or interference fit. Although this has not been illustrated, the bearing seat may also face axially outward.

The roller wall 13 accordingly extends between the idler shaft 16 and the shell 12. The bearings 22 rotatably support the roller walls 13 and shell 12 for rotation about the rotation axis X. The shell 12 may have a plurality of circumferentially spaced apart locating formations 30 provided on an axially inner surface of the shell 12 which serve to locate the roller walls 13 relative to the shell 12 in an assembled condition. The locating formations 30 may be in the form of lengths of flat bar welded or otherwise secured to the inside of the shell 12. The locating formations 30 limit a depth of penetration of the lip 19 of the roller wall 13 into the shell 12. In a preferred embodiment illustrated in succeeding drawings of the idler roller, the locating formations 30 are replaced by a circumferential groove formed in an outer periphery of the shell. In order to retain the roller walls 13 partially within the shell 12, ends of the shell 12 are pressed or crimped over the respective outer lips 19 in order to prevent their withdrawal from the shell 12. Accordingly, in this example embodiment, the shell 12 is rigid and made from metal. It is to be appreciated that any other suitably rigid material may be used for the shell 12.

Each bearing assembly comprises a bearing 22, a graphite or engineering felt seal 23, lip seal, or labyrinth seal etcetera, operatively received in the bearing seat 21 of the bearing housing 18, adjacent an inner periphery of the roller wall 13, in order to prevent ingress of foreign objects into the bearing seat 21 via the bore 15, and a retaining circlip 24 sprung into a groove axially inward of the journals on the shaft 16 in order to retain the bearing in place, in the case of a solid shaft. When a hollow shaft is used, journals may be machined down to form a step, shoulder or collar that locates the bearing.

The roller wall 13 is made from a polymeric, resiliently deformable material. In other words, the roller wall may be made from rubber having a suitable Shore hardness which permits resilient deformation when subjected to a load. Preferably the roller wall 13 is made from polyurethane. However, any means suitable to dampen movement between the shaft and the outer shell may be used such as rubber, polyurethane, metal spring, leaf spring etcetera. Preferably the Shore hardness of the roller wall must be between 55 and 95. The hardness of the roller wall may be altered to suit different applications. The roller wall 13 therefore acts as a shock absorber when a load is applied to the shell 12 and permits the shell 12 to be radially, laterally or transversely displaced by a displacement distance Z1 relative to the shaft 16 in the direction of the applied force, as can be seen illustrated in dotted lines in Figure 2, in order to absorb the shock. Less force or strain is therefore transferred to the bearings 22 which prolongs the life of the bearings and prevents deformation of the shaft 16 and damage to the conveyor belt. The displacement distance Z1 may range from between 0.04 ^* R1 and 0.35 ^* R1 in response to a load being applied to the tubular outer shell 12.

A second embodiment of an impact absorbing idler roller 100 is illustrated in figure 5. The same reference numerals used above have been used again in figure 5 to refer to similar features of the idler roller 100. The primary difference between the idler roller 10 and the idler roller 100 illustrated in figure 5 is the roller wall 130. The roller wall 130 is made from resiliently deformable material and includes a radially inwardly disposed bearing housing 18. The wall 130 further includes a circumferentially extending, radially outwardly disposed lip 190 which defines a broad abutment surface 191 which operatively engages an inner surface of the shell 12 and a shoulder or collar 192 which is configured to mate with an operatively crimped end of the shell 12. A non-linear or V-shaped shock absorbing zone 200 extends between the bearing housing 18 and the lip 190. A dust cover 40 closes off an axially outer end of the roller 100 and has a locating formation in the form of a protruding ridge which engages with a complementary groove in the roller wall 130, tongue-in-groove fashion. An adhesive may be applied to the bearing seat 21 in order to prevent dislodgement of the bearing 22 from the bearing seat 21 when a load is applied to the roller 100. Similarly, adhesive may be used at an interface of the abutment surface 191 with the shell 12. In the light of the collar 192 and broad abutment surface 191 , there is no need for locating formations on the shell in order to keep the roller wall 130 in position.

With reference to figures 6 to 1 1 , reference numeral 300 refers generally to a third embodiment of the impact absorbing idler roller in accordance with the invention. The idler roller 300 includes a rigid, metallic, tubular outer shell 312 defining a central shell axis Y (see figures 9 to 1 1 ) and an elongate hollow idler shaft 316 which defines a longitudinal shaft axis which coincides with the rotation axis X. The idler roller 300 further includes a pair of resiliently deformable impact absorbing roller walls 313 which extend radially between the idler shaft 316 and the outer shell 312, proximate ends of the outer shell 312. Each roller wall 313 defines a central bore for accommodating the idler shaft 316. The impact absorbing roller walls 313 are configured to support the tubular outer shell 312 for rotation about the rotation axis X. To this end, each roller wall 313 has a radially inwardly disposed bearing housing 318 for receiving a bearing assembly comprising a bearing 22 and an engineering felt seal 23 in an axially inwardly facing bearing seat 321 defined by the bearing housing 318. Each roller wall 313 also includes a shock absorbing zone 320 which extends radially inward from an outer periphery of the roller wall 313 to the bearing housing 318.

The shock absorbing zone 320 includes an inclination which extends radially inward from the outer periphery of the roller wall 313 toward the bearing housing 318. In the example embodiment illustrated in figures 6 to 1 1 , the inclination is axially inwardly slanted from the outer periphery of the roller wall toward the bearing housing 318. To this end, the shock absorbing zone 320 includes an axially inwardly slanted annular wall 322 which is configured to limit axial movement of the idler shaft 316 relative to the tubular outer shell 312 when subjected to loads.

The roller wall 313 is a unitary piece made from polymeric material, such as rubber or preferably polyurethane. Accordingly, the bearing housing 318 is integrally formed with the shock absorbing zone 320. The outer periphery of the roller wall 313 includes a circumferentially extending lip 330 which is configured to mate with an end of the tubular outer shell 312. The tubular outer shell 312 includes a circumferentially extending groove or depression 340 which is rolled into an outer circumference of the shell 312, proximate each end thereof. The grooves 340 serve as gripping formations which retain or secure the roller walls at least partially within the shell 312 by way of an interference fit.

The idler shaft 316 has journals 344 at opposing ends thereof for receiving the bearing assemblies. The journals 344 are formed by machining end portions of the shaft 316 away to form a shoulder or collar 346 which locates the bearing 22 on the idler shaft 316 and limits axial inward movement relative to the shaft. The shaft 316 also has a pair of diametrically opposing indentations 347 pressed into ends of the shaft 316 which allow the impact absorbing idler roller 300 to be quickly and easily installed and removed from a mounting bracket which has corresponding mounting formations for receiving the indented ends of the shaft 316. Dust covers 335 slid over opposing ends of the shaft 316 prevent ingress of dust particles into the bearing assemblies.

As illustrated in figures 9 to 1 1 , the roller walls 313 are resiliently deformable to permit shock absorption when the idler roller 300 is subjected to loads. Figure 8 depicts the idler roller 300 in a normal operating condition in which the idler shaft axis X and the central shell axis coincide. As mentioned before, the impact absorbing idler roller 300 is intended to be used at a material handling transfer point of a conveyor or at another suitable position along the conveyor where a greater degree of force or impact is applied to the rollers. Accordingly, as shown in figures 9 to 1 1 , the tubular outer shell 312 of the idler roller 300 may be subjected to varying loads which are absorbed by the roller walls 313. The hardness of the roller walls 313 may vary depending on the intended application. Figure 9 depicts shock absorption of the roller walls 313 when subjected to normal loads where the central shell axis Y is displaced relative to the idler shaft axis X by a displacement distance Z2. The tubular outer shell 312 has a radius R2. In figure 10 an increased load has been applied which has resulted in a displacement distance Z3 between the shell axis Y and the idler shaft axis X. The displacement distance may range from between 0.04 ^* R2 and 0.35 ^* R2 in response to a load being applied to the tubular outer shell 312. The idler roller 300 can also be subjected to uneven loads applied to the outer shell 312 as depicted in figure 1 1 which will result in angular displacement of the shell 312 relative to the shaft 316. From figures 9 to 1 1 , it is clear that upper portions of the shock absorbing zone 320 of the respective roller walls 313 resiliently compress to absorb loading forces whilst opposing lower regions expand or lengthen.

Due to the axially inwardly slanted annular wall 322 of the shock absorbing zone 320 of the roller wall 313, the bearing assembly is urged axially inward into abutment with the shoulder 346 when the idler roller is subjected to loads. This urging force exerted on the idler shaft 316 from both ends prevents or limits relative axial movement between the idler shaft 316 and the outer shell 312.

Figures 12 and 13 illustrate a fourth embodiment of an impact absorbing idler roller 400 in accordance with the invention. In this instance, two independent roller bodies, each comprising a tubular outer shell 412 and a pair of resiliently deformable impact absorbing roller walls 413 secured to ends of the bodies, have been mounted to a single idler shaft 416 at axially spaced apart positions. Multiple roller bodies on the single idler shaft 416 increase the load bearing capacity of the conveyor idler roller 400 as a whole. The roller walls 413 each have a bearing housing for receiving a bearing 22 which includes a pair of annular discs 425 which are received in complementary grooves on an axially outer side of the bearing housing. An engineering felt seal 423 is sandwiched between the discs 425. The bearing 22 and discs 425 are arranged on opposite sides of a circlip 430 mounted in a circumferential groove in the shaft 416 which effectively limits axial movement of the outer shell 412 and roller wall 413 relative to the idler shaft 416. The roller walls 413 have an axially outwardly inclined annular wall 422 in a shock absorbing zone 420 which means that the bearing 22 is urged into abutment with the circlip 430 when subjected to loads. It is to be appreciated that any number of roller bodies may be supported on a single idler shaft 416. The hollow idler shaft 316 is cheaper than a solid shaft, is more resistant to vibration and is less prone to heat build-up, especially when ends of the shaft 316 are not capped or closed off. By way of example, a typical idler roller may have an outer diameter of 127 mm and an idler shaft diameter of 25 mm. Normal load bearing displacement of the outer shell relative to the idler shaft for this idler roller will be in the range of 0 - 6 mm. Maximum displacement may be in the range of 0 - 18mm. Relative displacement beyond 18 mm would mean the roller is overloaded. Due to installation of the bearing 22 in the axially inwardly facing bearing housing 18, 318 of the roller wall from the inside, the bearing 22 is less prone to contamination by dust and other foreign particles. For this reason, relatively cheap and simple dust covers 40, 335 can be used to seal off an axially outer side of the bearing housing. This obviates the need for complex and expensive labyrinth seals which are required for conventional idler rollers having bearings which are installed from the outside into axially outwardly facing bearing housings.

The Applicants believe that the impact absorbing idler roller 10, 100, 300, 400 in accordance with the invention has the following advantages over existing rollers:

• Fires are less likely due to the use of a metallic outer shell and a polyurethane roller wall and bearing housing.

• Less polymeric material is used to construct the roller 10, 100, 300, 400 which lowers manufacturing costs and makes the roller more affordable.

• Less Fire Retardant, Anti-Static (FRAS) additives will be used due to the roller consisting of less polymeric material which again provides a cost saving. FRAS rated rollers may therefore become a feasible option which would improve safety of the conveyor.

• The inclusion of a resiliently deformable shock absorbing zone distinguishes the invention from the prior art and provides an enhanced cushioning effect.

• The shock absorbing zone of the impact absorbing idler roller 10, 100, 300, 400 has improved shock absorption due to its resilience/elastic deformation when compared to conventional impact rollers and uses less material for impact absorption which results in a cost saving.

• The roller 10, 100 provides greater yield due to the resilience or shock absorbing ability of the roller walls 13, 130, 313, 413 to relieve stress from the bearings and shaft hence prolonging roller life and greatly reducing conveyor belt damage. • The tubular outer shell and roller walls can still rotate about ceased bearings seated within the respective annular bearing housings which prevents damage to the conveyor belt until the ceased bearings can be replaced.

Instead of conventional inflexible walls, the resiliently deformable walls 13, 130, 313, 413 of the idler roller 10, 100, 300, 400 greatly enhance its ability to absorb shock and remove stress from the bearings, shaft and conveyor belt.