The invention relates generally to the field of imaging, and in particular to an imaging apparatus employing an idler roller system. More specifically, the invention relates to an imaging apparatus with an idler roller assembly employing a self-securing bearing retainer.
Light sensitive photothermographic film is used in many applications ranging from photocopying apparatuses to graphic arts to medical imaging systems. For example, laser imagers are widely employed in the field of medical imaging to produce visual representations on photothermographic film of digital image data generated by various scanners, such as magnetic resonance imaging (MRI) scanners and computer tomography (CT) scanners. Laser imagers typically include some type of film supply system, a film exposure system, a film processing system, and a transport system that moves and guides film through the laser imager along a transport path from the supply system and through the exposure and processing systems to an output.
Transport systems generally employ one or more spring-loaded roller sets that form a portion of and transport film along the transport path through the laser imager. Such roller sets typically consist of a urethane coated drive roller and some type of idler roller system including a urethane coated idler roller which is held in contact with the drive roller. One such idler roller system includes a bearing retainer which holds a bearing and fits into and slides in an opening in a side wall of the imaging apparatus. A shaft of the idler roller extends through the bearing and bearing retainer and includes one machined groove, adjacent to the bearing retainer and positioned exterior to the imaging apparatus and one machined shoulder adjacent to the bearing retainer but within an interior of the imaging apparatus. To secure the bearing retainers and shaft within the imaging apparatus, a clip, or e-ring, is installed in the machined grooves on each end of the idler roller shaft.
While such an idler roller system is effective at securing the bearing and idler roller, the use of multiple e-rings and corresponding grooves make it relatively costly to manufacture and the cumbersome nature of installation makes it relatively costly to assemble. In light of the above, there is a need for an improved idler roller system and, in particular, an improved bearing retainer.
An object of the present invention is to provide a bearing retainer having a reduced number of components so as to decrease manufacturing costs.
Another object of the present invention is to provide a bearing retainer which simplifies installation processes so as to decrease assembly costs.
These objects are given only by way of illustrative example, and such objects may be exemplary of one or more embodiments of the invention. Other desirable objectives and advantages inherently achieved by the disclosed invention may occur or become apparent to those skilled in the art. The invention is defined by the appended claims.
According to one aspect of the invention, there is provided a bearing retainer. The bearing retainer includes a flange having a front surface and a rear surface, a hub extending from the front surface and having an exterior surface to receive and support a looped extension spring and having an interior forming a bearing pocket, and at least one resilient finger initially extending from the rear surface and having a curve so as to extend toward and beyond the front surface and including at least one retainer tab extending from a surface opposite the hub and positioned on the rear surface side relative to the flange. The resilient finger is configured to be deflectable from a free position toward the hub in response to a deflection force to enable a portion of the resilient finger including the retainer tab to be inserted through an opening in a wall and to substantially return to the free position upon release of the deflection force such that the wall is held between the retainer tab and rear surface, thereby securing the bearing retainer within the opening.
According to once aspect of the invention, the hub includes a spring retainer flange extending radially outward from an end of the hub opposite the front major surface of the flange. According to one aspect of the invention, the hub is positioned so as to limit deflection of the at least one resilient retainer finger from the free position to a distance less than a distance which would cause permanent deformation of the at least one resilient retainer finger.
According to one aspect of the invention, the bearing retainer includes a frame element extending from the rear major surface, wherein the frame element is configured to extend through the opening when the bearing retainer is secured within the opening and is configured with dimensions to provide a sliding fit within the opening.
According to one aspect of the invention, the bearing pocket is configured to receive and hold a bearing via an opening in the rear surface. According to one aspect of the invention, the bearing is configured to receive a shaft via the opening, and wherein the shaft is free to rotate within the bearing.
According to one aspect of the invention, the bearing pocket is configured as a bearing and is configured to receive a shaft via an opening in the rear surface, and wherein the bearing pocket is configured to support the shaft and to allow rotation of the shaft therein.
According to one aspect of the invention, the bearing retainer is formed from a single piece of material. According to one aspect of the invention, the bearing retainer comprises a plastic material. According to one aspect of the invention, the bearing retainer comprises an anti-static polycarbonate.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following more particular description of the embodiments of the invention, as illustrated in the accompanying drawings. The elements of the drawings are not necessarily to scale relative to each other.
The following is a detailed description of the preferred embodiments of the invention, reference being made to drawings in which the same reference numerals identify the same elements of structure in each of the several figures.
Processing system 36 receives exposed film 40 from exposure system 34 and develops the latent image thereon. In one embodiment, processing system 36 comprises a thermal processor, such as a drum-type processor, which heats exposed film 40 to thermally develop the latent image. Processing system 36 subsequently cools and delivers the developed film along transport path 42 to output system 38 (e.g. an output tray, sorter) for access by a user. Imaging apparatus 30 employs at least one roller set 44 having a drive roller 46 and an idler roller assembly 48, according to embodiments of the present invention, including an idler roller 49 which, together with drive roller 46 form a portion of a transport path 42.
A frame element 76 extends from rear surface 64 of flange 60 and is configured to slideably insert and extend through opening 58 (see
In one embodiment, bearing retainer 50 includes first and second resilient fingers 80 and 82. First and second resilient fingers 80 and 82 initially extend outward from rear surface 64 of flange 60 (see
First and second resilient fingers 80 and 82 each include at least one retainer tab extending outward from a surface opposite hub 66. In one embodiment, as illustrated, first resilient finger 80 includes retainer tabs 84 and 86 and second resilient finger 82 includes retainer tabs 88 and 90. First and second resilient fingers 80 and 82, along with their corresponding retainer tabs, are configured so to be deflectable toward hub 66 from a normally “free” or non-compressed position where first and second resilient fingers 80 and 82 are spaced from hub 66. In one embodiment, flange 60 includes notches 83 and 85 into which first and second resilient fingers 80 and 82 respectively travel when deflected from their non-compressed position (see
In one embodiment, bearing retainer 50 comprises a plastic material. In one embodiment, bearing retainer 50, including flange 60, hub 66, frame element 76, and first and second resilient fingers 80 and 82, is formed from a contiguous piece of material. In one embodiment, bearing retainer 50 is formed using an electro-static discharging polycarbonate material so as to prevent static build-up during transport of film 40 along transport path 42. In one embodiment, bearing retainer 50 comprises anti-static acetal plastic.
As typically defined, a material's yield strength or yield point refers to a stress point of the material. Upon application of a stress which is below the yield point, the material will elastically deform and return to its original shape when the applied stress is removed. However, if the yield point is exceeded, some fraction of the deformation will be permanent and non-reversible. In one embodiment, as illustrated by
Returning to
In one embodiment, to assemble idler roller assembly 48, idler roller 49 is positioned such that shaft 56 extends through opening 58. Bearing 52 is positioned within bearing pocket 72 inside hub 66 and bearing retainer 50 is slid onto shaft 56 such that shaft 56 extends through bearing 52 and opening 74 in the end of hub 66. Compression forces 93 and 94 are applied to deflect first and second resilient fingers 80 and 82 toward hub 66 until distance D296 between outermost points of retainer tabs 84 and 86 and retainer tabs 88 and 90 is less than distance D3100 between outside edges of notches 97 and 98. Subsequently, first and second resilient fingers 80 and 82 are inserted into corresponding notches 97 and 98 and frame element 76 is inserted through opening 58 until rear surface 64 of flange 60 contacts an exterior surface 102 of endplate 59, at which point retainer tabs 84 and 86 and 88 and 90 have respectively passed through corresponding notches 97 and 98. It is noted that flange 60 has dimensions exceeding those of a main portion (excluding notches 97 and 98) of opening 58.
Compression forces 93 and 94 are subsequently removed such that first and second resilient fingers 80 and 82 substantially return to the free position so that distance D1 between outermost points of retainer tabs 84 and 86 and retainer tabs 88 and 90 is greater than distance D3100 between outside edges of notches 97 and 98. At this point, endplate 59 is retained between rear surface 64 of flange 60 and retainer tabs retainer tabs 84, 86, 88, and 90 such that bearing retainer 50 is secured within opening 58.
As mentioned above, frame element 76 is configured with a “running” or “sliding” fit within opening 58 whereby the dimensions of frame element 76 are incrementally smaller than the dimensions of opening 58 such that frame element 76 can move, or slide, within opening 58. In one embodiment, for example, frame element 76 has a clearance relative to opening 58 ranging from a minimum of 0.05 mm to a maximum of 0.21 mm. As such, after installing extension spring 54 about exterior surface 68 of hub 66 and stretching and coupling extension spring 54 to anchor posts 110 and 112 via retainer loops 106 and 108, extension spring 54 biases (i.e. pulls) bearing retainer 50 in a direction toward anchor posts 110 and 112, thereby biasing idler roller 49 against drive roller 46.
With reference to
By employing a self-securing bearing retainer, such as bearing retainer 50, having integrated resilient fingers with retainer tabs, such as first and second resilient fingers 80, 82 and retainer tabs 84, 86, 88, and 90, to secure the bearing retainer to a structure, an idler wheel assembly according to embodiments of the present invention, such as idler roller assembly 48 eliminates the use of e-rings and the need for corresponding grooves in the idler roller shaft. The self-securing nature of bearing retainer 50 also makes idler roller assembly 48 less cumbersome to assemble than conventional idler roller assemblies. As a result, an idler roller system employing a bearing retainer according to embodiments of the present invention has fewer components and is easier and less costly to assemble and manufacture than conventional idler roller assemblies.
The invention has been described in detail with particular reference to a presently preferred embodiment, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention. The presently disclosed embodiments are therefore considered in all respects to be illustrative and not restrictive. The scope of the invention is indicated by the appended claims, and all changes that come within the meaning and range of equivalents thereof are intended to be embraced therein.
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Number | Date | Country | |
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20080145099 A1 | Jun 2008 | US |