text: 1. Field of the Invention
  This invention relates to presses of the type having a frame and a slide element which is movable guidingly relative to the frame and, more particularly, to a bearing assembly that guides movement between the slide element and frame.
  2. Background Art
  There are many environments in which elements are translated guidingly, one relative to the other. As one example, presses utilize a slide element that is movable guidingly relative to a frame between extended and retracted positions. In one such press construction, the frame has a plurality of elongate, vertically extending columns which cooperate with the slide element to guide movement thereof. This type of press may utilize either flat surface-to-surface contact between the slide element and frame or roller elements that are each engageable with a cooperating surface on the frame to roll there against as the slide element is moved between the retracted and extended positions.
  These conventional systems are effective generally so long as exact alignment between the frame and slide element is maintained. However, in the event that the slide element becomes skewed, either because of misalignment of supporting parts and/or because of the application of an uneven force on the slide element during use, the slide element may bind within the frame. This potentially has a number of deleterious effects. The skewed slide element may not move smoothly relative to the frame. Over time, guiding elements acting between the frame and/or slide element may suffer significant damage. In a worst case, the skewing could be extreme enough that the press malfunctions.
  To address the above condition, frequent maintenance may have to be implemented to keep the press operational. In the event of a malfunction, the press might have to be shut down and repaired. This may have a significant economic impact on a business, particularly when the press is an integrated component of an overall machining system that coordinates the press operation with processing performed by a number of other machining components.
  Many systems have been devised to facilitate smooth relative translational movement between press elements. As one example, U.S. Pat. No. 3,389,625 (Wagner) discloses a roller carrying element on a frame, which element can be adjustably cammed so as to control clearance between roller elements thereon and a cooperating, translating slide element. It appears that in both of Wagner""s embodiments, the orientation of the pivot axes for the roller elements can vary relative to a truncated, cylindrical camming element, which is repositioned so as to press the roller elements toward the slide element. This reorientation of the roller elements during operation of the system could impair the intended smooth guiding function of the roller elements.
  It also appears that Wagner""s structure would be prone to skewing by shifting of the slide element out of the plane of the paper, as seen from the FIG. 2 perspective. The roller elements acting against the side edges of the slide element are responsible for preventing skewing in two orthogonal planes. In a high load environment, it would be difficult, if not impossible, to construct a system of this type that would effectively control skewing in orthogonal planes by reason of using only the opposing relationship on the side edges, as depicted in Wagner.
  The press industry, and other industries, are constantly seeking ways to smoothly and positively guide relative translatory movement between cooperating elements.
  In one form, the invention is directed to a press system having at least one elongate column. A slide element is guided by the at least one column between a retracted position and an extended position. A first guide assembly acts between the slide element and the one column. The first guide assembly has a) a first bearing assembly consisting of a first bearing housing on one of the slide element and one column, a first carrier that is guidingly movable relative to the first bearing housing, and a first roller element that is movable guidingly relative to the first carrier and acts against a first surface on the other of the slide element and the one column to guide movement between the slide element and frame as the slide element is moved between the retracted and extended positions, and b) a second bearing assembly consisting of a second bearing housing on one of the slide element and the one column, a second carrier that is guidingly movable relative to the second bearing housing, and a second roller element that is movable guidingly relative to the second carrier and acts against a second surface that is i) on the slide element in the event that the second bearing housing is on the frame and ii) on the frame in the event that the second bearing housing is on the slide element.
  In one form, the first and second surfaces are transverse to each other.
  The first carrier may be guidingly movable relative to the first bearing housing around a first axis.
  The second carrier may be guidingly movable relative to the second bearing housing around a second axis that is transverse to the first axis.
  In one form, the first and second axes are substantial orthogonal to each other.
  In one form, there is at least one roller element on the first bearing assembly in addition to the first roller element that is movable guidingly relative to the first carrier and acts against the first surface to guide movement of the slide element as it is moved between the retracted and extended positions.
  The press element may be movable in a first substantially straight line between the extended and retracted positions. The first and second axes may be substantially orthogonal to the first straight line.
  In one form, the first roller element is movable relative to the first carrier around an axis that is substantially fixed relative to the first carrier.
  In one form, the frame has three elongate columns in addition to the one elongate column and there is a guide assembly, the same as the first guide assembly, acting between the slide element and each of the three columns in addition to the one column.
  In one form, there is a second guide assembly, the same as the first guide assembly, acting between the slide element and the one column.
  The invention is also directed to a press system having a frame, a slide element that is guided by the frame between a retracted position and an extended position, and a first bearing assembly acting between the slide element and the frame. The first bearing assembly has a first bearing housing on one of the slide element and the frame, a first carrier that is connected to the first bearing housing for pivoting movement relative to the first bearing housing around a substantially fixed first axis, and a first roller element that is connected to the first carrier for pivoting movement relative to the first carrier around a second substantially fixed axis and acts against a first surface on the other of the slide element and the frame to guide movement between the slide element and frame as the slide element is moved between retracted and extended positions.
  In one form, the first carrier has an arcuate, concave surface which guides the first bearing housing in pivoting movement around the first axis.
  The first bearing housing may be fixedly attached to the one of the slide element and frame.
  The system may further include a first mounting block releasably attached to the one of the slide element and frame. The first bearing housing is attached to the first mounting block so that the first bearing housing can be adjusted and maintained in a desired position relative to the first mounting block.
  The press system may further include a second bearing assembly, that is the same as the first bearing assembly, and having a second bearing housing. The press system may further have a second mounting block that is in a fixed position on the one of the slide element and frame, with the second bearing housing being attached to the second mounting block so that the second bearing housing can be adjusted and maintained in a desired position relative to the second mounting block.
  The slide element may have first and second transverse surfaces. In one form, the first mounting block is attached to the first transverse surface with the second mounting block attached to the second transverse surface.
  The invention is further directed to a bearing assembly for acting between a slide element and another element to guide movement of the slide element and another element between first and second relative positions. The bearing assembly has a first bearing housing for attachment to one of the slide element and the another element, a first carrier that is connected to the first bearing housing for pivoting movement relative to the first bearing housing around a substantially fixed first axis, and a first roller element that is connected to the first carrier for pivoting movement relative to the first carrier around a second fixed axis and acting against a surface on the other of the slide element and another element to guide movement between the first and second relative positions.
  In one form, the first carrier has an arcuate, concave surface which guides the first bearing housing in pivoting movement around the first axis.
  The invention is further directed to a method of guiding relative movement between a slide element and a frame having at least three elongate columns which are located around a space within which the slide element is movable between an extended position and a retracted position. The method includes the steps of: providing a plurality of bearing assemblies that cooperate one each between the slide element and each elongate column; and rotating a roller element on each bearing assembly around an axis and against one of a) the slide elements and b) one of the columns to guide relative movement between the slide element and frame as the slide element moves between the extended and retracted positions.
  The method may further include the steps of varying the orientation of the axes of the roller elements relative to the one of a) the slide element and b) one of the columns to accommodate skewing of the slide element as the slide element is moved between the extended and retracted positions.