Abstract:
A joint device for coupling a cover with a body of a scanner. The joint device has a pivot means to enable the cover be lifted upward to a height desired according to the thickness of the scanning document. The pivot means has inner walls closed to the interior of the scanner so that outside dusts and dirts won&#39;t seep into the scanner. Scanner mechanism may be prevented from contamination and may maintain high scanning quality. The pivot means is simply structured with fewer materials and may be made at less time and low cost.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to a joint device for coupling a cover with a scanner body and particularly to an improved joint device that has a pivot means to enable the cover to turn for open or close smoothly and that may be made with less material and cost. 
     2. Description of the Prior Art 
     Scanner is a widely used computer peripheral device nowadays. With explosive growth of computer utilization and continuous drop of computer price, how to keep the cost and price of the scanner low while still maintain sufficient function and quality becomes a great challenge to scanner producers. 
     For low price scanners now available in the market, they usually have a joining device for coupling the cover of the scanner with the scanner body. One of the such joining devices is fixing one edge of the cover to one side of the body like a hinge. When in use, another edge of the cover that is free may be lifted to turn about the hinged edge for open or close the cover. While it may function well for one page or thin document, it is awkward for scanning a thick document such as a book. In such a situation, the cover will be inclined slantly and not fully cover the scanning surface. Scanning light cannot be distributed evenly, and outside light source may create further light distribution problem on the scanning surface and results in poor scanning quality. 
     In order to resolve the aforesaid problem, a number of solutions have been introduced in the market place. One of such examples is to divide the cover in two or more foldable and hinged sections. The cover may be flexibly lifted to a height desired to suit different document thickness. Such structure will increase cost. For low price scanner, the foldable sections generally are limited to two. Its functional improvement is also limited. 
     Another conventional example is shown in FIGS. 1 and 2. The scanner body  1  has a plurality of pivot sockets  10  provided at a side wall  14  of the scanner. At the top surface of the body  1 , a transparent board  12  is provided for supporting scanning document. The cover  2  mainly includes a cover plate  22  and a plurality of pivot means  20  located thereunder engageable with the pivot sockets  10 . Each of the pivot means  20  has a pair of spaced legs  24  extended downward from the bottom of the cover plate  22  and joined by a foot  25  at the distal ends thereof. Below the foot  25 , there is a stopper  26  fixedly located thereunder. Each of the pivot sockets  10  includes a pair of spaced upper openings  110  at the top and a pair of spaced slots  116  formed thereunder for accommodating the legs  24 . In the pivot socket  10 , there is a gap  113  which enable the foot  25  to pass through. For assembly, the pivot means  20  is held at a selected angle to enable the foot  25  to pass through the gap  113 , then the cover  2  is turned to horizontal to lay upon the scanner body  1 . 
     The pivot socket  10  further has a stop tongue  112  and a stop foot  115  located respectively above and below the gap  113  for preventing the pivot means  20  from disengaging with the pivot socket  10  when the cover  2  is horizontally laid on the scanner body. Inside the pivot socket  10 , there is a through slot  114  formed in the inside wall of the socket  10 . When in use, the stopper  26  is inserted in the through slot  114  which serves as a guard to limit the stopper  26  tilting position so that the cover  2  may be lifted and tilted to an angle desired. As the pivot socket  10  has ample interior space to allow the foot  25  moving up or down, the cover  2  may be held horizontal over the transparent board  12  even for scanning a thick document. 
     However it creates new problems. The through slot  114  must be formed in the inside wall of the pivot socket  10  to accommodate the stopper  26 . It exposes scanner inside mechanism to ambient environment. The scanner mechanism may easily be contaminated by dusts and dirts seeping through the through slot  114  and results in downgrade of scanning quality or even scanner malfunction. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of this invention to provide a joint device that has an improved pivot means which is simply structured and may prevent scanner inside mechanism from contamination by external dusts and dirts. 
     The joint device according to this invention includes at least one pivot socket located at a top portion of a side wall of the scanner body. The pivot socket has a pivot shaft located in a trough formed in the side wall. The trough has closed inner walls without communicating with interior of the scanner body. The pivot shaft has substantially rectangular crosssection with round corners and being shaped with two parallel flat upper and lower surfaces bordered by two curved side surfaces. The pivot socket further has a stopping flange extending from the top wall of the scanner body and above the trough. 
     The scanner cover has at least one engaging member located below a side edge for pivotally engaging with the pivot shaft. The engaging member looks like a narrow section of a rectangular duct but with a curved lower portion and a side slot at a side wall for the pivot shaft to pass therethrough. 
     When in use, the pivot shaft is pivotally housed in the engaging member which may be moved up or down so that the cover may also be moved up or down according to thickness of the scanning document. The cover may be kept horizontal against the scanning board to obtain best possible scanning quality. The engaging member may be turned about the pivot shaft smoothly at a selected angle during scanning operation. As the pivot socket does not lead to inside of the scanner body, scanning mechanism won&#39;t be contaminated by outside dusts and dirts. Scanning quality may be maintained at high level even after long time of use. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The invention, as well as its many advantages, may be further understood by the following detailed description and drawings in which: 
     FIG. 1 is an exploded perspective view of a conventional joint device for coupling a cover with a scanning body. 
     FIG. 2 is an enlarged perspective view of the joint device shown in FIG.  1 . 
     FIG. 3 is a schematic sectional view of a scanner using this invention. 
     FIG. 4 is an exploded perspective view of this invention. 
     FIG. 5A is a sectional view of a first embodiment of this invention. 
     FIG. 5B is another sectional view of the first embodiment shown in FIG. 5A, with the cover lifted. 
     FIG. 6A is a sectional view of a second embodiment of this invention. 
     FIG. 6B is another sectional view of the second embodiment shown in FIG.  6 A. 
     FIG. 7A is a sectional view of a third embodiment of this invention. 
     FIG. 7B is a sectional view of the third embodiment of this invention, for assembly the joint device in the scanner. 
     FIG. 7C is a sectional view of the third embodiment of this invention, for installing the scanner cover. 
     FIG. 7D is a sectional view of the third embodiment of this invention, for completing assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     This invention offers an improved joint device for coupling a cover with a scanner body that has simpler structure to reduce production time and cost. 
     FIG. 3 illustrates the joint device according to this invention that includes a pivot means  30  located at a juncture of one side edge of the scanner cover  4  and one side wall of the scanner body  3 . 
     FIG. 4 shows more details of the pivot means  30 . On a side wall of the scanner body  3 , there is at least one pivot socket  31  (two are shown in FIG. 4) which includes a trough  39  which has closed inner walls indented into the scanner body  3  and a pivot shaft  36  held transversely in the trough  39 . 
     At one side edge of the cover  4 , there is at least one engaging member  40  attached thereunder. The engaging member  40  is shaped like a narrow section of a hollow rectangular duct but with a curved lower portion  35  and a side slot  401   b  formed in a side wall. The engaging member  40  is engageable with the pivot shaft  36  through the side slot  401   b  for nesting the engaging member  40  in the trough  39 . 
     FIGS. 5A and 5B show a first embodiment of this invention. The pivot socket  31  is located at an upper portion of a side wall of the scanner body  3 . It includes a trough  39  which has a side and a top opening, a vertical inner wall  34   a  and a horizontal inner wall  34   b . At the top of the socket body  31 , there is a stopping flange  32  extending horizontally from the top wall of the scanner body. In the trough  39 , there is a pivot shaft  36  engaged with two side walls of the trough  39 . The pivot shaft  36  is shaped like a rectangular bar with two parallel top and bottom walls  361   b  but with two curved side walls  361   a . The thickness between the walls  361   b  is less than that of the side walls  361   a.    
     The engaging member  40  is shaped like a narrow rectangular hollow duct extending downward from a bottom surface of one side of the cover  4 . However the lower portion of the duct is formed in a curved slide surface  35  and there is a slide slot  401   b  formed in a side wall that is slightly wider than the thickness between the walls  361   b  of the pivot shaft  36  and smaller than the thickness between the walls  361   a . The engaging member  40  forms an inside space  401   a  much larger than the crosssection of the pivot shaft, especially in the vertical direction. 
     For assembly, the side slot  401   b  is wedged against the pivot shaft  36  to have the pivot shaft  36  slipping into the hollow space  401   a  of the engaging member  40 . When the cover  4  is resting on the scanner body  3 , the slide surface  35  makes contact with the horizontal inner wall  34   b . This is an idle or scanning position. When a thick document is placed upon the scanner for scanning, with cover  4  will be lifted upward. As long as the vertical displacement of the hollow space of the engaging member  40  is greater than document thickness, the cover  4  may remain substantially horizontal to fully cover the scanning board  12  (also shown in FIG. 4) for obtaining high quality scanning results. As the pivot shaft  36  is located at a different height level against the side slot  401   b , the engaging member  40  may be securely held without disengaging from the pivot means  30  through the side slot  401   b.    
     When the cover  4  is lifted and turned (as shown in FIG.  5 B), the cover  4  will be turned about the pivot shaft  36 . The slide surface  35  slides over the horizontal and vertical inner wall smoothly until the side slot  401   b  is located hitting the stopping flange  32  and the side surface  35  is located hitting the vertical inner wall  34   a . At this point, the cover  4  will be stopped for further turning. Depending on the angle of the side wall of the engaging member  40  which is formed by modulating the slide surface  35 , the stopping flange  32  and the vertical inner wall  34 , the cover  4  may be lifted and turned to an angle desired (the FIG. 5B, example shows about a 90 degree angle). It also helps to reduce cover damage which might otherwise happen when the cover  4  is swung non-stop abruptly. 
     Since the length between the curved surfaces  361   a  is greater than the width of the side slot  401   b , the pivot shaft  36  will not slip out of the side slot  401   b  during the cover lifting and turning operation. 
     As the inner walls  34   a  and  34   b  and side walls of the trough  39  is closed not to expose the interior of the scanner, dusts and dirts won&#39;t be seeped into the scanner. This further enhances scanning quality and reduces machine down frequency. It may result in lower operation and maintenance cost. 
     FIGS. 6A and 6B illustrate a second embodiment of this invention. It is constructed like the one shown in FIG.  5 A. Similar components will be marked by similar numerals. The engaging member  40  is formed like a reversed “U” shape but with a narrower and step lower portion which formed a slide surface  43 . The slot  401   b  is located at the bottom instead in a side wall. The pivot shaft  36  is skewed a selected angle crosssection wise. In the FIG. 6A, the skewed angle is 45 degree against a horizontal axis. This arrangement allows the engaging member  40  to engage with the pivot shaft  36  only at the selected angle and makes the disengagement between the cover  4  and the body  3  during scanning operation even more unlikely. 
     In the aforesaid two embodiments, the crosssection of the pivot shaft  36  is not circular. It has a larger dimension in X-axis and smaller dimension in Y-axis. The X-Y axes need not be horizontal and vertical. FIG. 5A shows X-axis is horizontal (with zero degree of skewed angle), and Y-axis is vertical (skewed angle is ninety degree). FIG. 6A shows the skewed angle is 45° for X-axis and 135° for Y-axis. 
     The pivot shaft  36  has a smaller dimension along the Y-axis (i.e. 135° skewed angle) and a larger dimension along the X-axis (i.e. 45° skewed angle). Hence when the slot  401   b  of the engaging member  40  is turned at the X-axis, the pivot shaft  36  may pass through the slot  401   b  to enable the engaging member  40  be engaged or disengaged with the pivot shaft  36 . Turning the slot  401   b  other than the X-axis, the pivot shaft  36  may not pass through slot  401   b , then the engaging member  40  may be hinged with the scanner without breaking away. 
     FIGS. 7A and 7B illustrate a third embodiment of this invention. It is substantially a mixed combination of the first and second embodiment set forth above. The engaging member  40  is shaped like the one shown in FIG. 5A but is a separate and detachable unit from the cover  4 . It is fixed to the cover  4  through a screw  5 . The pivot means  30  is largely like the one shown in FIG. 6A but with the pivot shaft  36  skewed 20 degree against the horizontal axis. After the engaging member  40  is skewed and engaged with the pivot shaft  36  (FIG.  7 B), the engaging member  40  is held upright for screwing with the cover  4  (FIGS.  7 C and  7 D). Then whatever angle the cover  4  being lifted and turned, it won&#39;t disengage with the pivot shaft  36 . 
     It is to be noted that the pivot shaft  36  is purpose fully having different dimensions in length and width for preventing it from incidentally slipping through the side slot  401   b  during scanning operation. Other crosssection such as ellipse and irregular polygons may also be used equally well. 
     It may thus be seen that the object of the present invention set forth herein, as well as those made apparent from the foregoing description, are efficiently attained. While the preferred embodiments of the invention have been set forth for purpose of disclosure, modifications of the disclosed embodiment of the invention as well as other embodiments thereof may occur to those skilled in the art. Accordingly, the appended claims are intended to cover all embodiments which do not depart from the spirit and scope of the invention.