Metal deforming – By use of roller or roller-like tool-element – With carrier for roller-couple or tool-couple
Reexamination Certificate
2003-01-10
2004-12-07
Tolan, Ed (Department: 3725)
Metal deforming
By use of roller or roller-like tool-element
With carrier for roller-couple or tool-couple
C072S241400, C072S252500, C492S001000
Reexamination Certificate
active
06826941
ABSTRACT:
The present invention relates generally to roller apparatus such as, for example, back-up rollers used to support work rolls.
Work rolls are used in tandem sets to shape metal through compressive forces. The supporting back-up rollers tend to have a relatively larger diameter than the work rolls. Back-up rollers must be capable of applying very high forces, as much as 300,000 pounds of force.
Conventional back-up rollers comprise a bearing in which the axle is received in the inner race and the outer race is received in the roller. Bearing elements such as ball or cylindrical members are rotatably received between the races so that the roller is rotatable relative to the axle. Since there are size constraints on the rollers, the wall thickness of each of the inner and outer races for back-up roller bearings is conventionally limited to typically no more than about ½ inch. Bearings, for example, for cam followers and bearing wheels, have been provided wherein the wall thicknesses of the inner and outer races have been in excess of 1 inch. The rigidity of a race is related to its effective wall thickness (which includes the thickness of an axle or roller to which it is rigidly mounted), and the bearing capacity is a function of the rigidity of the races. Thus, the capacity of such conventional back-up rollers is limited by the rigidity of the least rigid of the races.
Back-up bearings have been provided wherein the inner race is mounted over an axle and has a variable thickness ranging between about ¾ inch and about 1{fraction (1/16)} inch and wherein the outer race serves as the roller and has a variable thickness in excess of about 3 inches and the surface of which has a shore hardness of 78 to 83.
One type of back-up roller heretofore provided by Applicant to a customer comprises two spherical roller bearings with an inner race fitted to an axle and an outer race fitted to an outer shell or roller composed of AISI 4140 heat-treated steel having a Rockwell C hardness of 45. Both the bearing life and the shell life were however considered unacceptable. In order to improve the shell life and also hopefully the bearing life, the customer requested that the shell be made instead of cast 420 stainless steel having a Rockwell C hardness of 50. While this did improve the shell life, the bearing life nevertheless remained unacceptable to the customer.
Back-up rollers are placed at spaced positions both circumferentially about (from overhead and from the floor) and axially along the work rolls. Each back-up roller must be accurately positioned, both top to bottom and left to right, and custom precision grinding is required to achieve the necessary accuracy during every changeover.
As the back-up rollers wear and their outer diameters accordingly decrease, they do not bear as hard against the work rolls with the result that the work rolls are undesirably more prone to deflect. When this occurs, it has been necessary with conventional back-up rollers to replace a worn roller with a new one. It is, however, considered desirable to increase the useful life of the back-up rollers so that they may need replacement less often.
In order to extend the useful life of such a back-up roller, in accordance with the invention disclosed and claimed in the parent application, the height (distance from the back-up roller axle to the back-up roller circumference or radially outer surface) thereof was adjustable by rotating an eccentric mount through which the axle is disposed and thereby translating the roller in a radial direction thereof. In order to rotate the eccentric bushing, a pair of circumferential slots were provided in the eccentric bushing, and force was applied to the eccentric bushing at ends respectively of the slots to push the eccentric bushing in opposite circumferential directions respectively.
FIGS. 1
to
3
illustrate generally at
10
an assembly of a pair of back-up rollers
12
which are used to support work rolls in accordance with the invention disclosed and claimed in the parent application. It should be understood that an assembly may include only one, three, or any other number of rollers
12
. Work rolls
15
are rolls which perform work on material which is passed between the work rolls, for example, flattening a sheet of metal. In order to perform the work, suitable force must be applied to the material, and back-up rollers
12
apply force to the work rolls
15
to aid them in performing the work.
The assembly
10
includes a housing
14
comprising a generally rectangular base plate
16
to opposite sides of which are attached, such as by welding or other suitable means, a pair of side plates
18
each having a pair of semi-circular openings or arches, illustrated at
20
, in its upper edge for the mounting of the rollers
12
respectively. Illustrated at
29
are a plurality (the assembly is shown to have three) of beams at the ends and center of the side plates
18
respectively and about midway of the height thereof, each beam
29
extending between and suitably attached to the side plates
18
such as, for example, by welding for bracing the housing
14
. A pair of cap plates
22
are attached to the upper edge of each of the side plates
18
each by means of a pair of fasteners
24
the shanks of which are received in apertures
23
in the respective cap plate
22
and which threadedly engage threaded apertures
27
in the respective side plate
18
or by other suitable means. The fasteners
24
may, for example, be socket head cap screws the heads of which are received in counterbores in the cap plates
22
. Slotted (for receiving a screwdriver) plugs
25
are screwed into the upper portions of the bores to cover and protect the bolts
24
. The bottoms of the threaded apertures
27
are suitably vented, and the vent holes (not shown) are closed by vent plugs
31
. Each cap plate
22
has a semicircular opening or arch, illustrated at
26
, in its lower edge which is complementary to the opening
20
in the respective side plate
18
to provide a circular passage, illustrated at
28
, wherein the pair of passages
28
on one side of the housing are in alignment with the pair of passages
28
on the other side of the housing.
A bushing
30
is received in each of the passages
28
to rotatably (frictionally) engage the respective side plate
18
and cap plate
22
and extends axially inwardly a small distance beyond the inner side surfaces thereof. The axially inner corners of the cap and side plates
22
and
18
respectively are suitably chamfered, such as at an angle of about 45 degrees, as illustrated at
32
and
34
respectively. The bushing
30
has a circumferential ridge
33
extending from its radially outer surface which frictionally engages complementary notches
36
and
38
in the chamfered corners
32
and
34
respectively to locate the position axially of the bushing
30
and prevent its movement axially out of the assembly
10
.
An axle
40
is received within each respective pair of bushings
30
and is attached thereto to prevent relative rotation therebetween by a dowel
74
. By “dowel” is meant to include other suitable attachment devices such as a pin or key. The dowel
74
is received in a bore, illustrated at
75
, which extends diametrically across the axle
40
in each end portion thereof and in bores, illustrated at
77
, in the respective bushing
40
.
Rotatably positioned about the axially central portion of the radially outer surface of the axle
40
are a plurality of circumferential rings or groups of roller bearing elements
42
, preferably cylindrical. For example, there may be 8 side-by-side groups each having 22 roller bearing elements positioned circumferentially about the axle
40
. A thin flat washer-shaped spacer member, illustrated at
44
, is positioned between each group and the adjacent group of roller bearing elements
42
. The radially inner axle-engaging edge of each spacer member
44
is scalloped such as by a plurality of half-moon cutouts, similarly as illustrated at
145
in
FIG. 6
, spaced circumf
Simmons James C.
Tolan Ed
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