MANUFACTURING THE SAME

FIELD OF THE INVENTION

The present invention is generally directed to a cam follower for a ram of a metal can production necker. More specifically, the present invention is directed to a novel interface between a tire and an outer ring of the cam follower and a method of achieving the same.

BACKGROUND OF THE INVENTION

Metal cans are often produced as two piece cans which comprise a cylindrical can body with an integral bottom wall and a can top. The can is typically made from aluminum. Typically, curved sections are formed at the bottom and top of the can to increase its structural integrity. A can making machine, sometimes referred to as a necker, forms the curved sections of the can by progressively squeezing, i.e. necking, the can body between opposing ram bodies which squeeze the can. The ram typically includes one or more cam followers extending therefrom. The cam followers ride on a cam that is mounted on a cylinder. As the ram rotates about the cylinder, the cam follower rides on the cam, which is configured to move the ram back and forth.

Typically, the cam is inserted into a tire to enhance operation thereof. The tire facilitates a smooth transition of force between the cam and the remaining portion of the cam follower. Moreover, the tire inhibits wear of the cam, the remaining portion of the cam follower, the ram, and, more generally, the necker machine. A disadvantage of known cam followers for rams for necker machines is that over time and extended use, the tire tends to shift axially relative to the remaining portion of the cam follower, and more specifically the outer ring. If this problem is not corrected, it can lead to reduced performance of the necker machine, and can further require unscheduled or more frequent maintenance or repair.

SUMMARY OF THE INVENTION

The present invention resides in one aspect in a cam follower for a ram of a metal can production necker. The cam follower comprises an outer ring having an outer ring bearing surface and an exterior surface. The exterior surface defines a groove extending along at least a portion thereof. The cam follower includes an inner ring coaxially disposed at least partially in the outer ring and having an inner ring bearing surface. A plurality of rolling elements is disposed in an annular cavity between the outer ring bearing surface and the inner ring bearing surface. The plurality of rolling elements are in rolling engagement with the outer ring bearing surface and the inner ring bearing surface so that the outer ring is rotatable relative to the inner ring about an axis of rotation. A shaft is received in a bore in the inner ring and is fixed relative thereto about the axis of rotation. The outer ring is received in a tire. A least a portion of the tire is disposed in the groove to inhibit axial movement of the tire relative to the outer ring.

In some embodiments of the present invention, the groove extends around a circumference of the outer ring. In yet further embodiments of the present invention, the groove extends in a plane substantially perpendicular to the axis of rotation. In yet further embodiments of the present invention, the exterior surface of the outer ring defines a plurality of grooves extending along at least a portion thereof.

In some embodiments of the present invention, the tire is molded about the outer ring. In yet other embodiments of the present invention, the tire comprises nylon. In yet further embodiments of the present invention, an outside surface of the tire is crowned.

In one embodiment of the present invention, the outer ring comprises a first section defining a first outer raceway and a second section defining a second outer raceway. The inner ring comprises a first section defining a first inner raceway and a second section defining a second inner raceway. A first plurality of rolling elements is disposed between the first outer raceway and the first inner raceway. A second plurality of rolling elements is disposed between the second outer raceway and the second inner raceway In yet further embodiments of the present invention, the first plurality of rolling elements and the second plurality of rolling elements comprise balls.

The present invention resides in another aspect in a method of manufacturing a cam follower for a ram of a metal can production necker. The method includes the step of providing a bearing having an outer ring having an outer ring bearing surface and an exterior surface. An inner ring is coaxially disposed at least partially in the outer ring and has an inner ring bearing surface. A plurality of rolling elements is disposed between the outer ring bearing surface and the inner ring bearing surface. The plurality of rolling elements are in rolling engagement with the outer ring bearing surface and the inner ring bearing surface so that the outer ring is rotatable relative to the inner ring about an axis of rotation. The method further includes the step of disposing the bearing in a mold. A molding material is injected into the mold and the mold is cured to form a tire about exterior surface of the outer ring.

In some embodiments of the inventive method, the exterior surface of the outer ring defines a groove extending along at least a portion thereof and at least a portion of the tire is disposed in the groove to inhibit axial movement of the tire relative to the outer ring. In yet further embodiments of the present invention, the groove extends about a circumference of the outer ring. In yet further embodiments of the inventive method, the groove extends in a plane substantially perpendicular to the axis of rotation. In yet further embodiments of the present invention, the exterior surface of the outer ring defines a plurality of grooves extending along at least a portion thereof.

In some embodiments of the present invention, the exterior surface of the outer ring defines a protuberance extending along at least a portion thereof. The protuberance interfaces with the tire to inhibit axial movement of the tire relative to the outer ring. In some embodiments of the present invention, the protuberance extends about a circumference of the outer ring.

In some embodiments of the present invention, the protuberance extends in a plane substantially perpendicular to the axis of rotation. In yet further embodiments, the exterior surface of the outer ring defines a plurality of protuberances extending along at least a portion thereof. In some embodiments of the present invention, the molding material comprises nylon. In yet further embodiments of the present invention, an outside surface of the tire is crowned.

DESCRIPTION OF THE DRAWINGS FIG. 1 is partial cross sectional view of a cam follower in accordance with one embodiment of the present invention.

FIG. 2 is a side view of the cam follower shown in FIG. 1.

FIG. 3 is a perspective view of a ram in accordance with one embodiment of the present invention in which to cam followers are coupled thereto.

FIG. 4 is a front view of the ram shown in FIG. 3

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1-2, a cam follower 10 for a ram of a necker machine is shown and is generally designated by the reference numeral 10. The cam follower 10 includes a first roller bearing 30 and a second roller bearing 60. The first roller bearing 30 and the second roller bearing 60 are configured in a tandem configuration. That is they are side to side. In the embodiment shown, the first roller bearing 30 and the second roller bearing 60 are fixed relative to each other about a first axis of rotation A. The first roller bearing 30 comprises a first outer ring 40 having a first outer race 42, also referred to as a bearing surface, and a first exterior surface 44. The first roller bearing 30 further includes a first inner ring 50 having a first inner race 52, also referred to as a bearing surface. The first inner ring 50 is coaxially disposed in the first outer ring 40. A plurality of balls 54 are disposed between the first outer race 42 and the first inner race 52. The plurality of balls 54 are in rolling engagement with the first outer race 42 and the first inner race 52 so that the first outer ring 40 is rotatable relative to the first inner ring 50 about the first axis of rotation A.

The first bearing 30 comprises an interior set of seals 56 extending radially between the first outer ring 42 and the first inner ring 52 on either side of the first plurality of balls 54. The first bearing 30 further comprises an exterior set of seals 58 extending radially between the first outer ring 40 and the first inner ring 50 axially outside of the interior set of seals 56. The interior and exterior seals 56, 58 are configured to retain a lubricant inside an annular cavity 59 formed between the first outer race 42 and the first inner race 52 in which the first plurality of balls 54 is disposed. In the embodiment show, the seals 56, 58 comprise a low carbon steel, however, as can be appreciated by a person having ordinary skill in the art and familiar with this disclosure, the seals 56, 58, also referred to a shields, can comprise many different materials.

In the embodiment disclosed in FIG. 1, the second roller bearing 60 is similar in configuration to the first roller bearing 30. The second roller bearing 60 comprises a second outer ring 70 having a second outer race 72, also referred to as a bearing surface, and a second exterior surface 74. The second roller bearing 70 further includes a second inner ring 80 having a second inner race 82, also referred to as a bearing surface. The second inner ring 80 is coaxially disposed in the second outer ring 70. A second plurality of balls 84 are disposed between the second outer race 72 and the second inner race 82. The plurality of balls 84 are in rolling engagement with the second outer race 72 and the second inner race 82 so that the second outer ring 70 is rotatable relative to the second inner ring 80 about the first axis of rotation A.

The second ball bearing 60 comprises an interior set of seals 86 extending radially between the second outer ring 72 and the second inner ring 82 on either side of the second plurality of balls 84. The second bearing 60 further comprises an exterior set of seals 68 extending radially between the second outer ring 72 and the second inner ring 82 axially outside of the interior set of seals 86. The seals 86, 88 are configured to retain a lubricant inside an annular cavity 89 formed between the second outer race 72 and the second inner race 82 in which the second plurality of balls 84 are disposed. In the embodiment show, the seals comprise a low carbon steel, however, as can be appreciated by a person having ordinary skill in the art and being familiar with this disclosure, the seals 86, 88, also referred to a shields, can comprises many different materials.

In reference to the embodiment shown in FIGS. 1-2, although the cam follower 10 comprises a first ball bearing 30 and a second ball bearing 60, the present invention is not limited in this regard and, as will be appreciated by a person of ordinary skill in the art, many different configurations may be employed. For example, the present invention may by practiced using a cam follower having a single row of balls bearings. Or, for example, the present invention may be practiced using a cam follower having a ball bearing wherein a single continuous outer ring defines a first outer race and a second outer race, and a single continuous inner ring defines a first inner raceway and a second inner raceway.

In the embodiment shown in FIGS. 1-2, the outer rings 40, 70 and the inner rings 50, 80 comprise 52100 steel that is through hardened. The first plurality of balls 54 and the second plurality of balls 84 also comprise 52100 steel. In the embodiment shown, the balls 54, 84 are separated by a cage, as is commonly known in the art (not shown in the FIGS.). The cage comprises low carbon soft steel. It should be understood that the present invention is not limited to a cage, as different spacers, or no spacers, may be employed between the balls in the first plurality of balls 54 and the second plurality of balls 84. It should also be understood that the present invention is not limited to balls, as other types of rolling elements may be employed with the present invention, for example, needle rollers.

Although specific materials are disclosed herein, a person of ordinary skill in the art and familiar with this disclosure will understand that the present invention is not limited in this regard, and that other materials may be used with the present invention.

In reference to FIGS. 1-2, the first inner ring 50 comprises a first bore 51 extending therethrough, and the second inner ring 80 comprises a second bore 81 extending

therethrough. A shaft 90 is received through the first bore 51 and the second bore 81. In the embodiment shown in FIGS. 1-2, the shaft 90 is press-fit in the first bore 51 and the second bore 81 so that the first inner ring 50 and the second inner ring 80 are fixed relative to the shaft about the first axis of rotation A. The shaft 90, also referred to as a stud, extends between a first end 91 and a second end 96. The first ball bearing 30 and the second ball bearing 60 are received on the shaft 90 proximate to the first end 91 thereof. The shaft comprises a shoulder 92 projecting radially from the shaft between the first end 91 and the second end 96. After the second ball bearing 60 is received on the shaft 90 the second inner ring 80 abuts the shoulder 92 to inhibit axial movement of the ball bearings 30, 60 relative to the shaft 90. After the bearings 30, 60 are disposed on the shaft 90 and the second inner ring abuts the shoulder 92, a retainer ring 93 is fixedly received on the shaft 90 proximate to the first end 91 so the first ball bearing 30 and the second ball bearing 60 are disposed axially between the retainer ring 93 and the shoulder 92 to thereby inhibit axial movement of the ball bearings relative to the shaft.

The shaft 90 includes a face 94 at the first end 91 perpendicular to the first axis of rotation A. The face 94 comprises a recessed hexagonal socket 95 configured to receive a hex wrench, or the like, for rotating the shaft 90 about the first axis of rotation A. The shaft 90 further includes a plurality of threads 97 on a radial outside surface of the shaft 90. In this way, the shaft 90 can be received in a bore (not shown in the FIGS. 1-2) comprising a complementary thread pattern, or can similarly be received in a nut or the like having a complementary thread pattern.

The first ball bearing 30 and the second ball bearing 60 are received in a tire 100. The tire 100 has an outside surface 110. The outside surface 110 engages the cam (not shown in FIGS. 1-2) during operating of the necker in accordance with the present invention. The first exterior surface 44 and the second exterior surface 74 each have a plurality of grooves 46, 76 extending along a circumference of the outer rings 40, 70 in a plane perpendicular to the first axis of rotation A. In the embodiment shown, each outer ring 40, 70 includes two grooves 46, 76 in its exterior surface 44, 74. It should be understood, however, that the present invention is not limited in this regard, and that different configurations may be employed with the present invention. For example, each exterior surface 44, 74 may have more than two grooves 46, 76, or the first exterior surface 44 may have a single groove 46, while the second exterior surface 74 does not include any grooves. In the embodiment shown, the grooves 46, 76 are machined into the exterior surfaces 44, 74.

A portion 102 of the tire 100 is disposed in each groove 46, 76. This interface between the portion 102 of the tire 100 and the grooves 46, 76 inhibits axial movement of the tire 100 relative the ball bearings 30, 60 thereby improving the performance of the cam follower 10 in accordance with the present invention.

It should be understood that while the interface between the tire 100 and the exterior surfaces 44, 74 is defined as the exterior surfaces having grooves 46, 76 in which a portion 102 of the tire 100 is disposed therein to inhibit axial movement of the tire 100 relative to the bearings 30, 60, the present invention is not limited in this regarding. For example, the exterior surfaces 44, 74 may comprise one of more circumferential protuberances. In a similar fashion, portions of the tire surround the protuberances, thereby inhibiting axial movement of the tire relative to the bearings 30, 60.

In the disclosed embodiments, the tire 100 is molded onto the ball bearings 30, 60. The balls bearings 30, 60 are disposed in a mold configured to form a tire 100 about the first and second outer rings 40, 70. A molding material is injected into the mold and is then cured about the outer rings 40, 70 to form the tire 100. In the embodiment shown, the mold material is molten nylon, although, it should be understood that many different molding materials may be used with the present invention. During the molding process, the molding material solidifies in the grooves 46, 76, so that the portion 102 of the tire 100 is disposed in the grooves 46, 76. In this manner, the interface of the grooves 46, 76 and the portion 102 of the tire 100 disposed therein inhibits axial movement of the tire relative to the bearings 30, 60. In the embodiment shown, the outside surface 110 of the tire 100 is crowned to facilitate the rolling of the cam follower 10 relative to the cam (not shown) during operation of the necker in accordance with the present invention.

In reference to FIGS. 3 and 4 a ram assembly 200 for a necker machine (not shown) in accordance with the present invention is shown. In such a can making necker machine, a cam follower usually rides on a stationary cam with the rotational axis parallel to the cam's surface. The ram assembly 200 extends between a first end 210 and a second end 230. The ram assembly 200 includes a fixed bushing 220 having a bore extending therethrough between the first end 210 and the second end 230. A ram piston 214 extends through either end of the bore of the fixed bushing 220. Proximate to the second end of the ram 230, two cam followers 240, 250 (similar to the cam follower 10 illustrated in FIGS. 1-2 and described in detail herein) extend radially therefrom. The cam followers 240, 250 ride on a surface of a cam 260, one 240, 250 on each side of the cam 260, at the same time they are rotating around the cam's axis. The ram 214 is moved back and forth by the attached cam followers 240, 250 in an accelerating and decelerating movement following a profile of the cam 260.

Considerable radial force is developed on the cam follower 240, 250 during the can necking operation.

While the present disclosure has been described with reference to various exemplary embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims.