Abstract:
A lid and lid drive mechanism for a portable, hand held device pivots a flat cover on the device in a predetermined controlled manner between a first position covering at least portion of the front of the device and a second position in which the cover extends towards the rear of the device. The drive mechanism comprises a spring/damper mechanism which pivots the cover of the device in a predetermined controlled manner between the first position and the second, thus forming a stand raising the top end of the device above a horizontal support surface upon which it rests. The top end of the device frame has left and right inwardly facing extension which enclose a first and second cylindrical hollow cavities. A coiled drive spring is located in one hollow cavity which a damping mechanism utilizing a damping drum and a viscous fluid is located in the second hollow cavity.

Description:
The present invention relates to a lid and lid drive mechanism for a portable, hand held device. The mechanism pivots a flat cover on the device in a predetermined controlled manner between a first position covering at least portion of the front of the device and a second position in which the cover extends towards the rear of the device. In the lids open position it can form a stand for tilting the device into an upwardly inclined position relative to a horizontal support surface upon which it may be placed. While the description relates primarily to the use of the lid to cover the display on a calculator it has application to a numerous different devices wherein it is desirable to protect operative features of the device when it is not in use. 
     BACKGROUND 
     U.S. Pat. No. 6,178,085 shows a calculator with a lid hinged to an upper end of the calculator housing. When the calculator is in its stored configuration the lid lays flat over a display panel located in the front surface of the calculator. Upon releasing the lid from its stored position, the lid pivots rearwardly in a controlled, damped manner about a hinge connection between the lid and the calculator frame. The pivoting motion is driven by a torsion spring and damping drum arrangement located within a tubular bore within the hinge portion of the lid. 
     Des 426,849 to Lee shows a calculator, similar in outward appearance to the &#39;085 patent. However, since it is a design patent the mechanical features of the opening mechanism is not shown. 
     Hollingsworth, U.S. Pat. No. 5,607,054 discloses a carrying case for a notebook computer having a front panel adapted to be folded rearwardly to form a stand to support the notebook computer in an inclined position. 
     Nelson, et al., U.S. Pat. No. 5,568,358 discloses a portable signal processing communications unit having a hinged cover which can be folded to form an inclined supporting structure for maintaining the unit in a upwardly tilted position during use when located on a horizontal supporting surface. Nelson includes a helical coil spring in a cylindrical bore in the lid but does not include a damping means 
     Loh, et al., U.S. Pat. No. 5,530,234 discloses a hand held calculator with a cover adapted to extend over the entire front surface of the calculator when the calculator is not in used. When the calculator is used, the cover is slid towards one end of the calculator along longitudinal side grooves in the calculator housing. The cover can then be rotated so it extends below the rear of the calculator to form a stand or support. 
     Narishima, et al., U.S. Pat. No. 4,703,160 shows a casing structure on a portable electronic appliance, such as a small hand held portable calculator, wherein portions of the casing are hinged to each other so they can be folded backwardly in order to form a supporting stand for maintaining the calculator or device in an inclined or tilted position during use on a support surface 
     Dynesen, U.S. Pat. No. 4,259,568 discloses a portable or pocket calculator having a casing structure including hinged cover. The cover portions are adapted to be folded rearwardly when the calculator is placed on a horizontal surface, providing a stand. 
     JP57-143626 to Murakami shows a calculator with a pivoting lid that serves as a cover as well as a stand. The helical coil spring in a cylindrical bore in the assembly appears to provide a friction damping function. However, it appears that the lid must be manually rotated about the hinge. 
     U.S. Pat. No. 4,390,289 to Houlihan show an elastomeric washer in a cylindrical bore along with a tightening screw. The lid can be manually rotated rearwardly up to about 350° to allow the device to stand on a surface at any desired angle to that surface. 
     U.S. Pat. No. 5,732,135 to Weadon et al—Shows a hinge configuration for a lid on a portable telephone. The housing has a pair of openings to receive movable pins mounted in a tubular portion of the lid. A coil spring in the tubular portion provides friction on the pins. 
     Many attempts been made to develop devices capable of properly moderating the movement of a lid, causing the lid, on release from its closed position, to be opened smoothly yet steadily and slowly. These devices typically make use of mechanical frictional force and incorporate rods in cylinders filled with oil. 
     U.S. Pat. No. 6,085,384 to Bivens shows a hinge damper comprising a blind cylindrical bore with a damping drum in that bore and a damping means within the cylindrical bore, that damping means being a viscous silicone oil or other viscous damping fluid or gel. The hinge arrangement is in a channel across the end of a lid or door that is pivotally attached to a stationary structure. 
     U.S. Pat. No. 3,118,167 shows a hinged structure with a cylinder formed integral with a longitudinal edge. A spindle is disposed coaxially within the bore of the cylinder. The space between the cylinder and the spindle is filled with a fluid-damping medium. A coil spring is located on the spindle so that it drives the hinge in one direction (closed), its torsional force being moderated by the fluid-damping medium. 
     U.S. Pat. No. 3,860,993 to Matuska is directed to a door opener that biases a door to an open position using a coiled spring with the opening action dampened by a viscous fluid. The device comprises a tubular portion extending along the longitudinal axis thereof with damping means in a cylindrical bore. The damping means comprising a helical coil spring in the bore, one end of the spring being secured against rotation to a bottom surface of the bore, and a damping drum connected to the opposite end of the spring. An enclosed space between the rotor and the inner wall of the cylinder is filled with a viscous silicone that damps the opening action of the spring. 
     U.S. Pat. No. 5,142,738 shows a still further example of a damped hinge. comprising a case with a rotatable cylinder therein, a high viscosity grease in a gap between the case and the rotatable cylinder A coil spring is mounted between the case and the rotatable cylinder. 
     U.S. Pat. No. 5,165,507 is yet another example of a hinge construction incorporating a cylindrical case, a damping drum, a coil driving spring and a viscous damping fluid. 
     U.S. Pat. No. 5,230,159 shows a calculator mounted to the surface of a tape measure. The calculator includes ribbed gripping surfaces  54 ,  56  along the outer edges of the housing. 
     In addition, numerous small electronic devices have been available for several years that include a hinged lid with a drive mechanism to open the lid once a latch is released. For example, Prodart of Hong Kong has offered various small calculators that include various pivoting portions, including covers and displays, which include a coil spring drive mechanism to effect opening. However, the damped drive is provided by a gear mechanism operatively attached to the lid. Several of these devices have a coil spring drive enclosed within a tubular portion at the hinged edge of the movable portion. 
     SUMMARY 
     The invention contemplates an improved dampened drive construction for the lid on an electronic device such as a calculator. The device has a generally flat surface including buttons for inputting data or operational instructions, electronics for manipulating the input data or instructions, a display window for viewing the information entered, the calculated results or information received or desired to be displayed, and a cover, which covers at least the display window, pivotally mounted to the calculator frame. A spring/damper mechanism pivots the cover of the device in a predetermined controlled manner between first position overlying the display window and a second position in which the cover extends to the rear of the device, thus forming a stand raising the top end of the device above a horizontal support surface upon which it rests. Upon releasing the lid from its first position, the spring drives the lid around pivot points, to its second position. The damping mechanism moderates the speed of the pivoting movement of the lid. The upper end of the device frame includes two tubular channels spaced apart along a common axis with a hinge portion of the lid located in the space between the channels. The spring is located in one of the tubular channels in the frame, with a first end of the spring attached to the bottom of the channel. The damping mechanism, in a preferred embodiment, has a first end located in the other tubular channel. Both the spring and the damping mechanism have a second end attached to the hinge portion of the lid. 
    
    
     
       DRAWINGS 
       These and other features, aspects and advantages of the present invention will become better understood with reference to the following description, appended claims, and accompanying drawings, where: 
         FIG. 1  is a front view of a calculator with a lid in its closed position, embodying features of the invention. 
         FIG. 2  is front view of the calculator of  FIG. 1 , with the lid in a partially open position, the hinge portion connecting the lid to the calculator body being shown in a cutaway view, so the spring/damper mechanism can be seen. 
         FIG. 3  is a partially cutaway right side view of the calculator of  FIG. 1  with the lid in a fully open position. 
         FIG. 4  is a left side view of the lid. 
         FIG. 5  is an enlarged front view of the cutaway portion of  FIG. 2  showing a further embodiment of the spring/damper mechanism attached to the lid. 
         FIG. 6  is a side view of an embodiment of a spring holder. 
         FIG. 7  is a left end view of the spring holder of  FIG. 6 . 
         FIG. 8  is right end view of the spring holder of  FIG. 6 . 
         FIG. 9  is an end view of the spring. 
         FIG. 10  is an end view of the spring. 
         FIG. 11  is a further enlarged view of the left portion of the cutaway view of  FIG. 5  showing the spring mechanism attached to the lid and calculator frame. 
         FIG. 12  is a further enlarged view of the right portion of the cutaway view of  FIG. 5  showing the damper mechanism attached to the lid and calculator frame. 
         FIG. 13  is a side view of an embodiment of the damper. 
         FIG. 14  is a left end view of the damper of  FIG. 13 . 
         FIG. 15  is a right end view of the damper of  FIG. 13 . 
         FIG. 16  is a view from the right side of the calculator of  FIG. 1  showing the retainer for the damper. 
         FIG. 17  is a cutaway side view of the retainer of  FIG. 16  taken along line  17 — 17  of  FIG. 16 . 
         FIG. 18  is an enlarged view of the left portion showing a further embodiment with the drive spring and damper at one side of the calculator. 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1–3  and  5  shows a portable, a hand-held calculator  10  including a generally flat and rectangular housing  12  and a lid or cover  14 . The lid  14  is movable from a first position covering a portion of the front of the calculator, primarily a display screen, to an open position to the rear of the housing  12 . The pivoting movement of the lid to its open position, as shown in  FIG. 3 , raises the top of the calculator  10  above a surface upon which the calculator is placed. The lid structure  14  is attached to the housing  12  by a hinge structure which includes a driving means, such as a coiled drive spring  16 , and a damping means  18 , such as a rotating drum  20 . The spring  16  and damping means  18 , in combination, drives the lid  14  from its closed position, as shown in  FIG. 1 , to its open position at a predefined speed. The damping means  18  prevents the lid  14  from rapidly snapping open as it would if driven by the spring alone, which could possibly damage the calculator. Also, when the calculator rests on a surface, the opening lid serves to raise the top end of the calculator off the surface, thus orienting the calculator in a more ergonomic orientation for use. 
     In a preferred construction, as best shown in  FIGS. 2 ,  5 ,  11  and  12 , the top end of the calculator frame  12  has left and right inwardly facing extension  28 ,  30 , the extensions enclosing a second cylindrical hollow cavity  26  and first cylindrical hollow cavity  22 , respectively. The first cylindrical hollow cavity  22  and the second cylindrical hollow cavity  26  share a common central axis. The lid has a centrally located cylindrical portion  32  that is adapted to be connected to the spring  14  and the rotatable drum  20 . The central cylindrical portion  32  of the lid  14  also shares the same common central axis. 
     The spring  16  is located in the second cylindrical hollow cavity  26  in the top end of the housing  12 . An inner end  34  of the spring  16  is attached to the bottom of the cavity  26  to prevent the inner end  34  of the spring  16  from rotating within the cavity. Attachment within the cavity may be accomplished by various different means. One preferred method is the use of a slot  36  in the bottom surface of the hollow cavity  26  sized to receive a transverse portion  38  of the spring. Other techniques include adhesive attachment or molding into or attaching the spring directly to a metal of plastic plug, which may be wedged into or attached to the bottom end of the cavity. The other end of the coil spring  16  is then attached to the centrally located cylindrical portion  32  of the lid  14 . The attachment may be directly to the cylindrical portion  32 . An alternative means of attachment is a cap  40  such as best shown in  FIGS. 5–8  and  11 . The particular cap  40  has a groove  42  on a first end thereof sized to receive a second traverse portion  38  on the second end of spring  16 . In the particular embodiment shown, the cap  40  also has an extension  44  on its second end. The extension  44  has a cross sectional shape to fit in a similar sized and shaped hole  46  on the end of the cylindrical portion  32 . The cross sectional shape may be round, or non-round, i.e. oval, triangular, square, etc. so that when the extension  44  is placed in the similar shaped hole  46  the extension  44  will not rotate within the hole  46 . As shown in  FIG. 8 , the extension  44  is 6-sided and the hole  46  is similarly shaped. The extension  44  may be adhesively secured or press fit into the hole  46  to assure that, once assembled the spatial relationship between the extension  44  and the hole  46  is fixed. As a result of such an arrangement, when the lid is released from its closed position the second end of the tensioned spring rotates causing the lid to the same extent. 
     For proper functioning of the inventive design it is not necessary that the cap  40  have an extension  44  which is inserted in a hole in the cylinder  32 . For example, one skilled in the art would recognize that an equivalent construction has an extension located on the end of the cylinder, with that extension being inserted in a hole in the cap  40 . One skilled in the art will also recognize that there are numerous alternative ways of attaching a spring retaining cap to the cylindrical portion  32  of the lid  14 . 
     Several different damping means can be provided. A first embodiment of the damping means utilizes a rotatable drum  20  placed within a first cylindrical hollow cavity  22  in the top end of the housing  12 . A circumferential space  24  between the outer wall of the drum  20  and the wall of the first cylindrical hollow cavity  22 , best seen in  FIG. 12 , is filled with a viscous material such as a silicone oil, viscous grease or a gel. Alternatively, this space can be filled with other materials that create friction between the surface of the outer wall of the drum  20  and the inner wall of the cavity  22  to retard its rotation within the first cylindrical hollow cavity  22 . While the first end of the drum  20  is free to rotate within the cavity  22 , the other end of the damping means is attached to the cylindrical portion  32  of the lid. Numerous attachment means can be used including those described above regarding the spring retaining cap  40 . However, it is also desirable that the drum be more permanently secured to the cylindrical portion of the lid. Therefore, it may be adhesively secured, press fit or formed as an integral extension of the cylindrical portion  32  of the lid  14 .  FIGS. 2 ,  5  and  12  show the drum  20  to be secured within a hole in the end of cylinder  32  with an extension  144  similar in Shape to the extension  44  on cap  40 . 
     While the spring and damping drum which comprise the driving means are shown to be located in left and right hollow cavities in the calculator housing, the invention contemplates that their locations can be reversed or both can be located in a single hollow cavity on one side of the housing, such as in the left side of the housing as shown in  FIG. 18 . The assembly can be alternatively located on the right side of the housing. This embodiment includes a drum  120  as an extension of the retaining cap  40 . The drive spring  16 , located within a hollow in the center of the drum  20  is attached to both the calculator housing  12  and the cap  40  in the manner as described above. Also, in a like manner, a viscous material is located in the space  124  between the outer wall of the drum  120  and the housing  12 . The other end of the lid, the right side in this instance, can be rotatably mounted to the housing by any manner of pivot known to the art. It is also contemplated that two such assemblies can be used with one spring/damper combination in the first cylindrical cavity  22  and the second spring/damper combination in the second cylindrical cavity  26 . 
     The calculator housing also includes a latching mechanism  58  to hold the lid in its first position, such as shown in  FIGS. 1 and 2 , covering a portion of the face of the calculator until the operator desires to open the lid. The latching mechanism  58  includes a lip which interacts with the edge of the lid  14  in its closed position and a tensioning spring  62  which biases the lip  60  to its latching mode. Pulling downward (the direction of the arrow in  FIG. 1 ) on the latching mechanism  58 , compresses the tensioning spring  62 , retracts the lip, releasing the lid  14  so it can be driven open by drive spring  16 . While the latching mechanism  58  is shown located on the face of the calculator one skilled in the art will recognize that it can be located in numerous different positions such as to the side of the lid rather than below the lid front edge. Alternatively, it can be located at the bottom end of the first or second hollow cavity  22 ,  26  so as to interlock with the damping drum or lid cylindrical portion  32  in its closed orientation. 
     In assembling the lid  14  to the calculator housing  12  the viscous oil, grease or gel is inserted in the hollow cavity  22 , the spring and damping mechanism are placed in the hollow cavities  22 ,  26 , the spring  16  and damping drum  20  being attached to the lid  14  with the lid in its closed, first configuration with the spring tensioned to an extent that the lid will be driven to its desired open position within a desired opening time period. The order of assembly depends on the particular construction of the components and the appropriate order for easy of assembly. Once the components are assembled, a retainer  70  is placed over the right side of the calculator with pins  72  inserted in receiving holes  74  in the retainer. A retention cylinder  76  on the top of the retainer  70  fits within a like sized opening in the frame used to insert the drum  20 , retaining the drum  20  and viscous material in the first hollow cavity  22 . The pins  72  are then flattened, locking the retainer  70  to the housing  12 . To close the lid one merely rotates it upwardly and forward, retensioning the drive spring  16 , until the lid  14  edge is captured under the lip  60 . 
     The above described lid and opening mechanism can be applied to various calculators&#39; designs which are well known to those skilled in the art. However, the inventive lid is not limited to covering just the display on calculators but may also be applied to cover other operative features of the calculator such as some or all of the data entry buttons on face of the calculator. In its open position, it is also not necessary that the lid rotate about 270° to a position approximately perpendicular to the back of the calculator. The assembly can be designed to rotate the lid so the lid rests against the back of the calculator or to rotate to less than to a rearwardly perpendicular position if so desired by tensioning the drive spring  16  a greater or lesser amount and providing mechanical stops  64  to limit the rotation of the lid  14 . It is also contemplated that the lid and spring/damping mechanism can be applied to other electronic devices such as portable phones, pagers, hand held computers, data storage devices, electronic writing pads, compact disk display devices, sound recorders and audio and video player systems or non-electronic devices such as note pads, photo display collections and battery powered light sources. Accordingly, the invention described herein is not contemplated to be limited a particular application but is instead directed to a readily openable lid having a damped spring drive mechanism for protecting the operative surface of a device or display.