US3601247A

US3601247A - Live roller conveyor

Info

Publication number: US3601247A
Application number: US21961A
Authority: US
Inventors: Richard W Lowrie
Original assignee: Navigate Inc
Current assignee: Navigate Inc
Priority date: 1970-03-23
Filing date: 1970-03-23
Publication date: 1971-08-24
Anticipated expiration: 1988-08-24

Abstract

In a live roller conveyor wherein rollers each with an axle are held between a pair of rails, with drive means in engagement with the rollers, an arrangement to stop all or a group of previous rollers should one roller stop, to prevent excess pressure due to the bunching of material carried by the conveyor, comprising, live rollers generally spaced apart a distance less than the roller diameter; a guide rail under the live rollers; an arm connected to said guide rail having a free end; and at least one brake wheel disposed between succeeding live rollers and held by said arm, the center of the brake wheel being above the centerline of the live rollers, whereby, when one live roller is stopped, the brake wheel will wedge between the stopped roller and the roller immediately preceding it causing a chain reaction between all preceding brake wheels and the corresponding rollers.

Description

United States Patent [72] Inventor Richard W. Lowrle Clearwater, Fla. [2l] Appl. No. 21,961 [22] Filed Mar. 23, 1970 [45] Patented Aug. 24, 1971 [73] Assignee Navigate, Inc.

Clearwater, Fla.

[ 541 LIVE ROLLER CONVEYOR 5 Claims, 6 Drawing Figs. [52] US. 198/127, [98/26 [51] Int. Cl. 865g 13/02 [50] Field ofSearclL. 198/127 R, 34, 26

[56] Relerenoes Cited UNITED STATES PATENTS 3,337,023 8/1967 Kohl 198/127 R Primary ExaminerEdward A. Sroka Attorney-George B. Oujevolk ABSTRACT: In a live roller conveyor wherein rollers each with an axle are held between a pair of rails, with drive means in engagement with the rollers, an arrangement to stop all or a group of previous rollers should one roller stop, to prevent excess pressure due to the bunching of material carried by the conveyor, comprising, live rollers generally spaced apart a distance less than the roller diameter; a guide rail under the live rollers; an arm connected to said guide rail having a free end; and at least one brake wheel disposed between succeeding live rollers and held by said arm, the center of the brake wheel being above the centerline of the live rollers, whereby, when one live roller is stopped, the brake wheel will wedge between the stopped roller and the roller immediately preceding it causing a chain reaction between all preceding brake wheels and the corresponding rollers.

PATENTEDAUGZMQTI 3601.247

SHEET 1 0r 4 FIG. I

INVENTOR.

PATENTEDAUGZMHYI 360] I sum 2 0F 4 FIG. 2

PATENTED AUG24|971 3501' 247 SHEET 3 OF 4 FIG. 3

I N VEN TOR.

. PATENTEU M1824 I97! SHEET l [1F 4 FIG. 5

FIG. 6

LIVE ROLLER CONVEYOR BACKGROUND OF THE INVENTION The present invention relates t alive roller conveyor system, and more particularly to a live roller conveyor system wherein the stopping of one package on the conveyor will automatically stop all or a group of preceding packages on the conveyor so as to prevent jamming and excessive pressure on the stopped package.

BRIEF DESCRIPTION OF THE PRIOR ART Live roller conveyor systems are well known and are extensively used in the transportation of boxes and packages. In some cases, the boxes and packages transported must e stopped at a work station, e.g., for filling or emptying the box, or for other purposes. It is important at this time, to stop or accumulate the boxes behind the one that has stopped so as to prevent excessive pressure on the stopped package or box. I-Ieretofore, this problem has been attacked by rather complex and costly solutions requiring expensive equipment and mechanization.

SUMMARY OF THE INVENTION Generally speaking, in a live roller conveyor wherein live rollers each with an axle and a friction driven roller are held between a pair of rails, with drive means in engagement with the live rollers, the present invention contemplates an. arrangement to stop a certain group of previous rollers should one roller stop, to prevent excess pressure of the material-carried by the conveyor. This arrangement comprises live rollers which are spaced apart a distance generally less than the roller diameter; a guide rail under the live rollers; an arm connected to said guide rail having a free end; and at least one brake wheel disposed between succeeding live rollers and heldby said arm, the size of the brake wheel being such that the brake wheel will generally not extend above a line tangent to the live rollers, the center of the brake wheel being above the centerline of the live rollers whereby, when one live roller is stopped, the brake wheel will wedge between the stopped roller immediately preceding it, causing a-chain reaction between all preceding contiguous brake wheels and the corresponding rollers.

The invention as well as other objects and advantages thereof will become more apparent from the following detailed description when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic side illustration of the principles of operation of the roller conveyor including the brake wheel mechanism contemplated herein;

FIG. 2 is a cutaway perspective illustrating the principles of operation of the roller conveyor of FIG. 1;

FIG. 3 is an exploded view of one of the rollers used herein;

FIG. 4 shows an exploded view of one of the brake wheel assemblies used herein; and,

FIGS. 5 and 6 show alternate mechanizations of a multiple brake wheel arrangement.

DETAILED DESCRIPTION CHAIN AND SPROCKET DRIVE Shown in FIGS. 1 and 2 is a roller conveyor 10 mounted on a base 12 which could be the floorof a building. The base 12 supports the roller conveyor 10 horizontally, by supporting a pair of

parallel side rails

14 and 16 used to hold live rollers 18, disposed normal to the rails and the structural components used in the system. One of the rails 16 has a chain guard 20. The rails have mounted thereon ball bearing pillow blocks 22 which are equally spaced apart. Each pair of bearings hold a roller 18. As shown in FIGS. 2 and 3 roller 18 consists of an inner steel axle 28 the ends of the axle being supported by the pillow blocks 22, two intermediate wooden plug bearings 30 and an outer hollow cylinder 32. The intermediate wooden bearings 30 have a central aperture 34 slightly larger than the steel axle 28. The friction between the aperture 34 in the wooden bearings and the axle 28 is sufiicient to turn the roll 18 when the axle turns, but loose enough to permit slippage. Thus, the axle 28 can turn in aperture 34 without forcing the roll 18 to turn, if it is held from turning with a light restraint. The outer cylinder 32 is firmly attached to the wooden bearings 30, and turns with the wooden bearings. Thus, if the inner axle 28 is turned, the roll 18 will also turn, and cause any package on the rollers to move along. If the package stops however, the rollers will stop while the axle will continue to rotate. Thus, the roll 18 is driven by a force equal to the wooden bearing friction, which force is related to the weight of the package on the roll.

Also mounted on the end of each axle 28 towards the chain guard section 20, as shown in FIG. 2 is a sprocket 36 driven by a chain 38. The chain 38 and sprocket are covered by the guard section 20 which will prevent packages from hitting the.

chain or sprocket. The chain is driven by conventional drive means not shown. An alternative roller drive, not involving the intermediate wooden bearings, is a conventional belt driven live roller system, where a flat belt is held in light contact with the lower surface of the rolls 18 by methods well known in the trade, In this live roller conveyor, if one of the packages traveling along the rollers should stop, without further mechanization, the packages behind the stopped package will bunch up and exert pressure on the front package. To keep the packages from exerting pressure on each other, a guide rail assembly 40 is mounted parallel to the frame members 14 and. 16. At intervals corresponding to the roller 18 spacing, holes 42 are provided in the guide rail assembly. Held by a bolt 44 in the hole 42 is one end of an arm 46 which extends upwards between two adjacent rollers. At the outer end of the arm 46 is an aperture for holding a small axle 48 for holding two brake wheels 50, one on each side of the arm 46. The brake wheels are preferably made of a slightly resilient material such as rubber.

Assume that a package is traveling along the roller conveyor. The brake wheels are so disposed between adjacent live rollers as shown in FIG. 1 that the bottom of the package only contacts the tops of the live rollers and passes over the brake wheels. If the package is stopped, one or more of the rollers 18 beneath the package will stop. When a roller stops, the preceding brake wheel is forced down by the friction between adjacent live rollers and becomes wedged between the two adjacent live rollers. This action stops the live roller immediately to the rear of the stopped roller so that the next brake wheel becomes wedged in between rollers and thus the stopping action is fed backwards to the last roller or to the point where a brake wheel is intentionally omitted. This is illustrated in FIG. 1, showing how when roller 18A is stopped, arm 46a is forced down by roller 18B until restrained by bolt 44 in hole 42. The diameter of the brake wheel with respect to that of the rollers is preferably such that the brake wheel will not protrude above a line tangent to the upper surface of the live rollers, i.e., the bottom of a box 52 carried by the live rollers. Although there is not limit to the size of the brake wheel, it generally should not have a diameter larger than the live rollers, and, the relationship shown in FIGS. 1 and 2, namely of the order of the one-half the diameter of the live rollers is most suitable.

The brake wheels may protrude above the carrying surface of the rolls if provision is made to avoid interference between the brake wheels and the flow of materials on the conveyor. The brake wheels can be confined to a given area of the roll by several means, including an arm extending down between the rolls, by an arm extending above the rolls, by simple lateral confinement with side plates, or by other similar means. Somewhat improved results occur when the brake wheel is sized to fit between rolls sufficiently so that an appreciable amount of regenerative braking occurs. That is, when the roll in front of the brake wheel stops, the roll behind tends to force the brake wheel down between the rolls and into firm contact with both rolls. This firm contact serves to transmit the braking force from the forward roll to the rearward roll. With small brake wheels, vertical constraint is desirable to prevent the wheel from being forced completely down between the rolls when the braking action takes place.

The preferred brake wheel assembly is shown in FIG. 4. The wheel has a central bushing 54 with a central aperture and with an outer rubber body 56.

BELT DRIVE The embodiment shown in FIGS. 1 to 3 is applicable to a sprocket drive arrangement. In the case of belt driven live rollers, the live rollers 18 are supported in a conventional manner. A conventional drive belt engages and drives the bottom of the live rollers 18. Thus, the friction between the belt and the live rollers causes the rollers to rotate. The braking arrangement in the case of belt driven systems may be the same as that which has just been described. A modified arrangement is possible where the brake wheels, when depressed, cause the drive belt support rolls to be depressed also, thus reducing or removing the drive force of the belt from the stopped rolls.

BRAKING AND ACCUMULATION The basic action of the brake wheels as described above is to transmit rearward a braking action which stops the preceding rollers. In this mode of operation when the front package is stopped, all preceding packages on the conveyor also stop in place. It is desirably however in many applications to allow the packages to bunch up or accumulate behind the stopped package, with the provision that the pressure on the first package be kept very light to avoid breakage impact, crushing, or jackknifing. In the present invention such low-pressure accumulation is possible with a simple adjustment which limits the braking force caused by the brake wheel. The brake wheel is prevented from causing a complete stoppage of the roller by preventing it from moving vertically to the point where it is wedged tightly between rollers. If the rollers under the first package are allowed to turn slowly against the brake wheel friction then all preceding rollers will turn slowly also, allowing an accumulation of packages to occur. The brake wheel vertical constraint is readily obtained by moving the guide rail 40 lengthwise along the conveyor a short distance until the arm 46 is at an angle to the vertical such that its vertical motion during braking is restricted by the bolt 44. By proper adjustment of the guide rail, all brake wheels are adjusted simultaneously for the accumulation condition desired. Another form of accumulation is obtained by simple omitting a brake wheel at selected intervals along the conveyor. Packages will continue to move forward to the point of the omitted brake wheel even when the forward section rollers are braked to a solid stop by the brake wheel. This mode thus provides a segmented or zone accumulation action.

vMULTIPLE BRAKE WHEELS In the event the conveyor load rolls 18 are to be spaced more than one diameter apart, the same principle of braking can be used with multiple brake wheels as shown in FIGS. 5 and 6. Three brake wheels 50B in contact with each other and the rolls 18, are supported on a common arm 46A which is constrained by guides 60 to move in a vertical direction. The arm is supported further by a pin 44A attached to guide rail 40. A.slot in the lower end of arm 46A is provided to limit the vertical travel of the arm. A modification of the multiple brake wheel mechanization is to use only two brake wheels coupled with a short belt or chain 61 as indicated in FIG. 6.

I claim:

1. In a live roller conveyor wherein live rollers each with an axle and a friction driyen roller are held between a pair of rails, with drive means In engagement with the live rollers, the

improvement therein to stop all or a group of previous rollers should one roller stop, to prevent excess pressure of accumulated material carried by the conveyor, comprising in combination:

a. live rollers spaced apart a convenient distance;

b. at least one brake wheel disposed between succeeding live rollers, the center of the brake wheel being above the centerline of the live rollers, whereby, when one live roller is stopped, the brake wheel will exert a braking force between the stopped roller and the roller immediately preceding it causing a chain reaction between all preceding coupled brake wheels and the corresponding rollers.

2. The apparatus as claimed in claim 1, wherein said brake wheels are covered with a slightly resilient material.

3. The apparatus as claimed in claim 2, wherein brake wheels are constrained in vertical and horizontal movement by being attached to an elongated member which is connected at its lower end to a guide member under the rollers, said guide member and elongated member have a slot on one member and a rod on the other permitting movement of said rod in said slot as said brake wheel moves from a position of rolling between adjacent rollers to a position of wedging between two adjacent rollers.

4. An apparatus as claimed in claim 3, said elongated member being a flat arm with a brake wheel on each side thereof.

5. An apparatus as claimed in claim 1, wherein some or all of said live rollers have a chain driven sprocket at one end thereof.

Claims

1. In a live roller conveyor wherein live rollers each with an axle and a friction driven roller are held between a pair of rails, with drive means in engagement with the live rollers, the improvement therein to stop all or a group of previous rollers should one roller stop, to prevent excess pressure of accumulated material carried by the conveyor, comprising in combination: a. live rollers spaced apart a convenient distance; b. at least one brake wheel disposed between succeeding live rollers, the center of the brake wheel being above the centerline of the live rollers, whereby, when one live roller is stopped, the brake wheel will exert a braking force between the stopped roller and the roller immediately preceding it causing a chain reaction between all preceding coupled brake wheels and the corresponding rollers.