Stacking Mechanism

Abstract

A stacking mechanism for stacking a plurality of articles in a vertical stack includes an elevatable platform and a plurality of pairs of opposed rollers or pawls which are rotatable in one direction by the articles when the platform is elevated to position a course of the articles between the opposed rollers or pawls, but which do not rotate in the other direction when the platform is lowered. The rollers or pawls are urged against the articles in the course which is positioned between them, whereby successive courses may be added to the stack and the stack is supported by the rollers.

Description

BACKGROUND AND SUMMARY OF THE INVENTION

This invention relates to a stacking mechanism, and more particularly, to a mechanism for successively and progressively stacking courses of articles to form a vertical stack.

In the stacking of articles, such as bricks or the like, it is desirable that an entire course of the stack be added to the stack at the same time and that the stacking be rapidly and accurately accomplished mechanically.

The stacking mechanism incorporating the principles of our invention rapidly and accurately positions and adds entire courses of articles to form a vertical stack of the articles. The stacking mechanism of our invention obviates the need for manually stacking the articles and is relatively simple in construction, operation, and maintenance. Moreover, the stacking mechanism of our invention progressively adds entire courses of the articles to the bottom of the stack which is being formed while at the same time supports the entire stack of articles. The stacking mechanism of our invention includes pairs of spaced retaining rollers or pawls which are normally urged toward each other which are rotatable in one direction only to enable a course of the articles to be positioned therebetween and maintain the course therebetween once the course has been so positioned.

The stacking mechanism incorporating the principles of our invention includes stack retaining means having spaced opposed retaining elements positioned vertically above course elevation means, the latter of which is powered between a first position spaced beneath the stack retaining means and a second position in which a course of the articles to be stacked is moved by the course elevation means to a location between the spaced opposed elements. Urging means urges at least one of the retaining elements toward the other to frictionally maintain the course of articles positioned between the retaining elements when the course elevation means is moved from its second position, whereby successive courses of the articles may be added to the stack and the stack is supported by the retaining elements.

These and other objects, features and advantages of the present invention will be more clearly understood through a consideration of the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

In the course of this description, reference will frequently be made to the attached drawings in which:

FIG. 1 is a perspective view of a stacking arrangement including a preferred embodiment of stacking mechanism constructed in accordance with the principles of our invention;

FIG. 2 is a plan view of the stacking arrangement taken substantially along line 2--2 of FIG. 1;

FIG. 3 is a plan view of our stacking mechanism taken substantially along line 3--3 of FIG. 1 and in which one of the cylinders has been broken away to illustrate a sealed gas embodiment thereof;

FIG. 4 is a partially cut away plan view of one of the stack retaining rollers of out stacking mechanism;

FIG. 5 is a cross-sectioned elevation view of the roller taken substantially along line 5--5 of FIG. 4;

FIG. 6 is an elevation view of another embodiment of our invention which employs stack retaining pawls; and

FIG. 7 is a plan view of another embodiment of cylinder construction in which the cylinder has been broken away to show an urging spring therein.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As shown particularly in FIGS. 1 and 2, the stacking mechanism of our invention is employed in conjunction with a suitable linear conveyor which is, for example, of the powered roll type. The stacking mechanism is positioned in the line of flow of the articles which are to be stacked and which are conveyed along the conveyor. The stacking mechanism, generally 10, includes an article elevation platform 12 which is normally positioned intermediate the length of the conveyor 14 in the path of travel of the articles which are to be stacked. The platform 12 is generally rectangular in shape and of a size to accommodate at least one course C of the articles to be stacked, which may be by way of example building bricks. The surface of the platform is formed by a plurality of parallel idler rolls 16 such that when a course of the bricks moves toward the platform, the course continues to move until the entire course is positioned upon the platform as shown in FIGS. 1 and 2. To insure that the course is delivered in accurate lateral alignment with the platform 12, suitable guide structure 18 may be mounted upon the conveyor 14 upstream from the platform to direct each course of articles to the platform.

The elevation platform 12 is powered for vertical movement by a lift cylinder 20, such that the platform is moveable from the lower dot and dash line position shown in FIG. 1 in which the upper surface of the platform is generally coplanar with the conveying surface 22 of the conveyor to an upper solid line position in which the course of bricks on the platform is positioned at an elevation which is adjacent the plane of the stack retaining structure, generally 24, which will now be described.

The stack retaining structure 24 is mounted in spaced overlying relationship to the conveyor 14 and vertically above the elevation platform 12 by way of a plurality of suitable supports 26. The retaining structure includes a plurality of pairs of retaining elements in the form of opposed spaced rollers 28 and 30, one pair of rollers each being provided for each of the bricks in a given course C. The rollers 28 on one side of the retaining structure are mounted for rotation about a common axis upon a rigid frame 32, each roller being carried by a bracket 33 which is fixed to the frame 32. These rollers 28 need only be moveable rotationally and not longitudinally. The opposite rollers 30 are mounted for rotation upon individual brackets 34. The brackets 34, in turn are each mounted on reciprocal rods 36 which extend through a rigid frame 37 and the end of each rod extends into cylinders 38, which are also mounted on the frame. The cylinders may comprise sealed gas cylinders normally urges the rollers 30 individually toward their corresponding individual rollers 28, and provides for longitudinal movement of each of the rollers 30 independently of each other away from rollers 28 when a course is moved into position between the rollers. The individual and independent longitudinal movement of rollers 30 ensures that each roller will bear against the bricks and minimizes the effect of any oversize bricks which might be in the course.

Although each of the rollers 28 and 30 is rotatable, rotation is limited to only one direction by a ratchet-type mounting, the mounting of roller 30 being shown in detail in FIGS. 4 and 5. Each of the rollers comprises an annular hub 40 having a tire 42 bonded about the outer periphery of the hub and having an inner surface which is spaced relatively closely adjacent a fixed rotation shaft 44. The tire 42 may be formed of a suitable polymeric material, such as polyurethene, which will frictionally grab each of the bricks of the course as they are moved into position between the rollers 28 and 30. The inner surface of the hub 40 includes a plurality of axially elongated notches 46 spaced at equal intervals around the surface. The notches 46 are formed with an inclined surface 48 such that one end 49 of the surface is spaced closely adjacent the shaft 44 and the other end 50 of the inclined surface is spaced at a greater distance from the shaft, as shown in FIG. 5. Cylindrical roller bearings 52, having a diameter greater than the distance between end 49 and shaft 44, are positioned in each of the notches between the hub 40 and the shaft 44 and a suitable bearing separator seal 54 is located such as to seal the open ends of the hub 40 and separate the bearings 52 from each other. The shaft 44, in turn, is stationarily mounted between the parallel extending arms 56 of the bracket 34 by way of side opening apertures 58 and suitable locking flats 60.

It will be seen, referring particularly to FIG. 5, that when the roller 30 is rotated in the direction indicated by the solid arrow, the maximum depth of each of the notches 46 will move into overlying relationship with the roller bearings 52 and allow ready rotation of the roller about shaft 44. However, when an effort is made to move the roller 30 in the opposite direction as indicated by the dashed arrow, the roller bearings 52 will become wedged between the inclined surface 48 of the notches and the shaft 44 and further rotation will be prevented.

In operation, a course C of bricks to be stacked, is conveyed along the roll conveyor 14 from left to right as viewed in FIGS. 1 and 2. The course C will pass through guide structure 18 which laterally aligns the course with the elevation platform 12 of the stacking mechanism. Upon further movement, the course moves onto the rolls 16 of the elevation platform 12 which is lowered into coplanar relationship with the surface 22 of the conveyor and movement of the course continues until the entire course has been positioned upon the platform as shown by the dot and dash lines in FIG. 1.

At this point, power is supplied to the lift cylinder 20 and the course of bricks C is elevated from the dot and dash line position in FIG. 1 to the solid line position. As the course is elevated, each of the bricks in the course moves between its respective pair of rollers 28 and 30. Just prior to the entry of the bricks between the rollers, the rollers are spaced from each other by an amount which is slightly less than the width of the individual bricks due to the force exerted upon rollers 30 by the cylinders 38. As the bricks move upwardly, the sides of the bricks engage the tire 42 of each of the rollers 28 and 30 causing the rollers to rotate in the direction indicated by the solid arrow in FIG. 5 and urging rollers 30, against the force exerted by the cylinders 38, slightly away from rollers 28 in the horizontal direction so as to accommodate the bricks between the rollers.

When the course has been fully positioned between the rollers 28 and 30 as shown in the solid lines in FIG. 1, each brick of the course is firmly clamped between the rollers and is held in its original course position relative to the other bricks by the force exerted against the rollers 30 by cylinders 38.

Now when the platform 12 is lowered back to its dot and dash line position in FIG. 1, the course C will remain positioned between the rollers 28 and 30 since rotation of the rollers in the opposite direction indicated by the dashed arrow in FIG. 5 is prevented due to the wedging of the roller bearings 52 between the shaft 44 and hub 40. The tire 42 frictionally engages the sides of the bricks to prevent slipping of the bricks.

The aforesaid operation is then successively repeated, another subsequent course of bricks being urged upwardly by the platform 12 to upwardly displace the course of bricks which was previously held between the rollers, the rollers effecting support of the entire stack as the stack is being formed.

If desired to facilitate fork lift manipulation of the stack, periodically a course C' may be formed having voids V immediately following a wood platen P or the like such that the stack of bricks above the platen may be readily removed by the tines of a fork lift which are insertable into the voids V.

Also if desired, the elevation platform 12 may be elevatable to still a third higher position, as shown in the upper dot and dash lines in FIG. 1, to lift the stack free of the rollers 28 and 30 for manipulation by other suitable stack manipulating apparatus.

Referring to FIG. 6, another embodiment of stack retaining element is shown which includes a pair of pawls 62 and 64 which are pivotally mounted at one end about a suitable pivot pin 66. The other end of the pawls is knurled or otherwise toothed at 68. The toothed ends of the pawls 62 and 64 are spaced from each other and the pawls are normally urged into generally downward rotation by springs 70.

In the operation of the pawl arrangement, the course of articles C is elevated to a position between the toothed ends 68 of the pawls 62 and 64, as shown in FIG. 6. As the articles move upward, the pawls are rotated about their pivot pins 66 against the force exerted by springs 70 to allow entry of the course between the pawls. When the elevation platform 12 is again lowered, the pawls 62 and 64 will rotate only so far until their toothed surfaces 68 grip the ends of the articles, whereby the course is firmly gripped between the ends of the pawls and further rotation of the pawls is prevented. The lower course C is now ready to be urged upward by the next course of articles, as previously described, to form the stack, the formed stack being supported by the pawls acting upon the lowermost course.

It will be understood that although the invention has been described in terms of stacking bricks, the invention may be readily employed in the stacking of other articles. It should also be understood that the embodiments of the present invention which have been described are merely illustrative of a few of the applications of the principles of the invention. Numerous modifications may be made by those skilled in the art without departing from the true spirit and scope of the invention.

Claims

What is claimed is:

1. A stacking mechanism for vertically stacking a plurality of articles comprising,

course elevation means adapted to receive a course thereon having a plurality of articles therein,

stack retaining means including a plurality of pairs of spaced opposed retaining elements having frictional engaging means thereon and positioned vertically above said course elevation means, said pairs of elements being spaced horizontally from each other and being of a number substantially equal to the number of articles along the edge of a given course of articles,

power means associated with said course elevation means for moving said course elevation means between a first position spaced beneath said retaining elements and a second position in which the articles of said course are positioned between respective ones of said pairs of spaced opposed retaining elements, at least one of the elements of each of said pairs of opposed retaining elements being horizontally reciprocally moveable relative to the other of the elements in said pairs by the articles on said course elevation means when the course elevation means is moved to said second position to enable the articles to be moved between said retaining elements, and

urging means urging at least one of the elements of each of said pairs of retaining elements toward the other of said elements in said pairs independently of the other said pairs for firmly frictionally maintaining each of the articles along an edge of the course of articles positioned between respective ones of said pairs of opposed retaining elements when said course elevation means is moved from said second position, whereby successive plural article courses may be positioned between said elements to form a vertical stack of the articles supported by said elements.

2. The mechanism of claim 1 wherein the distance between said spaced opposed retaining elements is normally less than the width of the articles to be stacked, said distance being increased to substantially the width of the articles when a course of the articles is positioned between said retaining elements.

3. The mechanism of claim 1 wherein said urging means comprises a sealed gas cylinder compressibly acting upon said pairs of said opposed retaining elements.

4. The mechanism of claim 1 wherein said urging means comprises compressible spring means.

5. The mechanism of claim 1 wherein said retaining elements comprise a pair of opposed spaced rollers, and mounting means mounting each of said rollers for rotation in one direction by the articles when a course of the articles is moved upward between said rollers, but preventing said rollers from rotating in an opposite direction when said course elevation means is moved from said second position to said first position.

6. The mechanism of claim 5 wherein said rollers include a tire encircling each of said rollers for frictionally engaging said articles.

7. The mechanism of claim 1 wherein said course elevation means comprises a platform having a plurality of parallel rollers.