Abstract:
Screwdriver apparatus for screwing-in, or unscrewing, two or more screws simultaneously. Gear linkage is provided to cause appropriate rotation of a plurality of appropriately-supported parallel shafts to simultaneously rotate and operate upon screws, such as two screws holding a line card in a router or switch within a telecommunications system. The distance between the parallel shafts is adjustable and under control of the user of the screwdriver. Any kind of screwdriver blade, such as Phillips, flat, etc., can be attached at the ends of the parallel shafts, and the blades need not match each other for any given usage. Rotational power for the screwdriver can be supplied by a human user or by a machine. Use of this tool facilitates adding or removing the aforementioned line cards, and saves technician time. Application of this tool is not limited to line cards.

Description:
BACKGROUND 
       [0001]    In the telecommunication area, there are routers, switches, and other hardware items which contain line cards or printed circuit boards and the like. From time to time, these line cards are physically addressed, or accessed, by a technician with a screwdriver for purposes of installing or removing the line cards, or for other troubleshooting purposes. There are multiple screws, inserted into and/or through those cards, which hold those cards in place within their respective router, switch, etc. These screws need to be screwed-in tightly to mount a card or unscrewed completely to remove the card. 
         [0002]    In certain routers and switches there are two captive installation screws, displaced from each other, which are the above-noted screws that need to be tightened if being inserted into the card to hold it fixedly in place or need to be loosened if the card is targeted for removal. In many cases, the technician has to move his screwdriver back and forth many times between these two screws which are situated on a single card at two different locations, making only a few turns at each screw, to allow an even, or aligned, insertion or removal of the card and thereby avoid stripping the threads on the screws and/or on the screw receptacles. But, this can be a tedious process, particularly if the card and/or a mother-board to which the card may be connected, is crowded with components and/or wiring. That crowded environment calls for extra care when maneuvering a screwdriver back and forth within the wiring and components to achieve a mounting or a removal of that card. 
         [0003]    Thus, there is a need for a device which can be inserted into multiple screws simultaneously and used to unscrew or screw-in the multiple screws simultaneously. That would eliminate need for movement of a screwdriver back and forth from one screw to the other, and thereby reduce technician time while also reducing likelihood of stripping the screws. Applicants disclose such a screwdriver apparatus herein. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0004]      FIG. 1  is an exemplary schematic diagram of an embodiment of the screwdriver present invention; 
           [0005]      FIG. 2  is an exemplary schematic diagram of a portion of the outer structure of a rotatable shaft perpendicular to the shaft supporting the handle of the screwdriver in the embodiment of  FIG. 1 ; 
           [0006]      FIG. 3  is an exemplary schematic diagram of the inner structure of the rotatable shaft of  FIG. 2 ; 
           [0007]      FIG. 4  is an exemplary schematic diagram of a top view of a portion of the rigid T sleeve support shown in  FIG. 1 ; 
           [0008]      FIG. 5  is an exemplary schematic diagram of an alternative embodiment telescoping equivalent of the structure depicted in  FIGS. 2 and 3 ; 
           [0009]      FIG. 6  is an vertical cross sectional view of a portion of the telescoping structure of  FIG. 5 ; and 
           [0010]      FIG. 7  is an exemplary end view of a portion of the telescoping structure of  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0011]    In this description, the same reference numeral in different Figs. refers to the same entity. Otherwise, reference numerals of each Fig. start with the same number as the number of that Fig. For example,  FIG. 3  has numerals in the “300” category and  FIG. 4  has numerals in the “400” category, etc. 
         [0012]    In overview, preferred embodiments include apparatus and methodology for screwing-in or un-screwing multiple screws simultaneously. There is provided a plurality of rotatable shafts operatively interconnected by gear-linkage. A handle, supported by and enveloping one of the rotatable shafts, is provided and that handle is configured to be grasped by the hand of a user. There are screwdriver blades affixed to the ends of other rotatable shafts, the other shafts being substantially parallel to the one shaft, the handle-shaft. The other shafts are substantially equal in length to each other and displaced from each other by a distance established by the user. The screwdriver blades each engage and simultaneously rotate a different screw when the handle shaft is rotated by the user. The simultaneous rotation of the different screws can all be in the same rotational direction, or one or more of the plurality of screws can rotate in an opposite direction to the rotational direction of one of the screws. 
         [0013]    In a particular embodiment there are two parallel shafts with screwdriver blades and three gear boxes. A first of the gear boxes links the handle shaft with two other rotatable shafts that are substantially perpendicular to the handle shaft. A second gear box links one of the perpendicular shafts to one of the parallel shafts. A third gear box links the other of the perpendicular shafts to the other of the parallel shafts. 
         [0014]    This apparatus and methodology operate with two screws separated from each other and screwed-into to a planar structure, such as, e.g., a line card associated with, e.g., a router or switch included in a telecommunications network. The particular embodiment can be hand operated by a technician/user or can be power-driven. The particular distance between the two parallel shafts can be adjusted by the user to accommodate different separation distances between different pairs of screws. Certain standard line cards with standard distances between screws can be readily accommodated with selectable standard positions in the apparatus causing its screw blades to be aligned with the line card screws. Different style screw blades can be used to accommodate any wood screw or machine screw, such as those having, e.g., a Phillips head style or a flat-head style. One blade can be in accordance with one style while the other blade can be in accordance with any different style and this is achieved by plugging-in each blade into its receptive slot formed in the end of one of the parallel shafts. A single shaft screwdriver employing a receptive slot at the end of its shaft to receive one of a number of different-styled blades is commercially available. 
         [0015]      FIG. 1  is an exemplary schematic diagram of a first embodiment  100  of the screwdriver of the present invention. A rotatable shaft  101  supports handle  105  which envelopes the shaft. The handle is suitable for hand grasping, and rotatable force can be applied to the handle by a user, or the handle can be detached and the shaft can be motor-driven. (motor not shown) Rotatable shafts  102  and  103  are directed perpendicular to shaft  101  and are sometimes referred to hereinafter as “perpendicular shafts.” The perpendicular shafts are operatively linked to shaft  101  by way of bevel gears included in gear box  106 . The bevel gears and their gear box are standard. The axes of rotation of shafts  101 ,  102  and  103  are substantially co-planar. 
         [0016]    Shafts  101 ,  102  and  103  as well as gear box  106  are all contained within rigid-inverted-T-shaped-sleeve  104 , referred to hereafter as a T sleeve. The T sleeve can be made from metal or stiff plastic and configured with precise tolerance to permit rotational motion of all three shafts while, at the same time, offering rigidity and support to the screwdriver apparatus. If made from clear plastic, the T-sleeve can be transparent where the internally supported shafts  102  and  103  would be visible, as shown, and gear box  106  would have been shown as a solid line instead of a dashed line. If made from opaque plastic or metal, then gear box  106  would not be visible in this view as shown by hidden line  106  and shafts  102  and  103  would also not be visible and would have been shown as dashed hidden lines instead of the solid lines presented. In either case, the gears within gearbox  106  are not visible and are depicted herein only to enhance clarity of presentation. Bracing structure  104 ′ offers additional rigidity for T sleeve  104 . The three shafts can be appropriately lubricated to facilitate rotation within the T sleeve. 
         [0017]    Rotatable perpendicular shafts  102  and  103  are extended axially by way of extender shafts  102 ′ and  103 ′ respectively. The extension is made to accommodate length L, the distance between two screws to be inserted or removed. Shafts  102  and  103  can be configured to provide standard lengths only, or can also be configured to provide other adjustable or selectable lengths, to be described in connection with  FIGS. 2 ,  3  and  5 . Extender shafts  102 ′ and  103 ′ extend co-axially from ends  118  and  117  of perpendicular shafts  102  and  103 , respectively, and are operatively coupled to standard bevel gears in standard gear boxes  108  and  107 , respectively. The manner of connecting the extender shafts from perpendicular shafts  102  and  103  is detailed below. 
         [0018]    Gear box  107  is operatively coupled to rotatable shaft  109  and gear box  108  is operatively coupled to rotatable shaft  110 . Shafts  109  and  110  are parallel to each other and to rotatable shaft  101 . Shafts  109  and  110  are sometimes referred to hereinafter as “parallel shafts.” The axes of rotation of shafts  101 ,  109  and  110  are substantially coplanar. Shafts  109  and  110  are of equal length to each other and have mechanisms  119  and  120 , respectively, at the ends of their shafts, each for receiving and holding a screw-blade (not shown). Mechanisms  119  and  120  can be permanently magnetized, so that the screws being inserted or removed (assuming iron or steel screws) can be more easily manipulated. If a blade which is aligned with its respective screw is not perfectly aligned with the groove of its respective screw initially, merely rotating the blade shall align the blade with the groove. 
         [0019]    Viewing handle  105  from its end (top of  FIG. 1 ), it is clear that if a clockwise rotation is applied to the handle, then the gear arrangement causes a clockwise rotation of parallel shaft  110  and a clockwise rotation of parallel shaft  109 , without need for an additional gear-reversal mechanism. Similarly, a counterclockwise rotation applied to the handle produces counterclockwise rotations of both shafts  109  and  110 . However, one of the two gear boxes  107  or  108  could include additional direction-reversing gears (not shown), if there happened to be a need for other than both parallel shafts rotating in the same direction responsive to handle rotation. 
         [0020]    Truss connector or cross brace I  1  I connects (through hollow sleeves  113  and  115 ) parallel shaft  109  directly to perpendicular shaft  103 ′ and cross brace  112  connects (through hollow sleeves  114  and  116 ) parallel shaft  110  directly to perpendicular shaft  102 ′. Each hollow sleeve is cylindrically-shaped with an inner diameter having precise tolerance to permit rotational motion of its respective shaft while, at the same time, its connection via the truss support between rotating shafts prevents unwanted motion of the shafts. In other words, the two truss connectors eliminate unwanted motion of their respective parallel shafts relative to their respective perpendicular shafts while permitting rotational motion. 
         [0021]    In addition to the truss supports, or instead of the truss supports, a plastic or metal “snap-together-elbow” support (not shown) could be used over gear box  108  and over rotatable shafts  110  and  102 ′. Another plastic or metal “snap-together-elbow” support (not shown) could be used over gear box  102  and over rotatable shafts  109  and  103 ′. These elbows would provide a rigidity function with respect to gear boxes  107  and  108  and their respective rotatable shafts, similar to that function provided by T-support  104  with respect to gear box  106  and its rotatable shafts. 
         [0022]      FIG. 2  is an exemplary schematic diagram of a portion of the outer structure of rotatable perpendicular shaft  103  depicted in  FIG. 1  in accordance with the first embodiment. Perpendicular shaft  103  may be cylindrically shaped in its exterior and may contain a cylindrical cavity represented in  FIG. 2  by hidden dashed lines  204   a  and  204   b . In addition, shaft  103  may contain multiple apertures, such as apertures  201 ,  202  and  203 , also depicted by hidden dashed lines. These apertures, as well as similar companion apertures contained in shaft  102 , are not shown in  FIG. 1 , but they are holes which run from the inner cylindrical surface to the outer cylindrical surface of hollow cylinder  103  and a similar hollow cylinder for shaft  102  (not shown), and serve as detent positions for securing an extender shaft, described below. There may be more or fewer apertures than the three depicted, and they may be evenly or un-evenly spaced apart. The apertures may also be cylindrically shaped. These detent positions in combination with other detent positions in shaft  102  can be configured to provide lengths L that are standard lengths for standard line cards or standard lengths for other components secured by screws. The shafts could also contain other holes at other locations that would offer a variety of distances L, other than standard distances. This variety can be further augmented by a telescoping feature to be discussed in connection with  FIG. 5 . to be able to accommodate virtually any length L desired, within a maximum L limit. 
         [0023]      FIG. 3  is an exemplary schematic diagram of extender shaft  103 ′ which is the inner structure of rotatable perpendicular shaft  103  of  FIG. 2 . Extender shaft  103 ′ is a solid cylinder which supports spring-loaded buttons  301  and  302 . The buttons can be depressed into their respective cavities  301 ′ and  302 ′ by a screwdriver user, as extender shaft  103 ′ is inserted into perpendicular shaft  103 . The left-hand side of extender shaft  103 ′ fits inside the right-hand side of perpendicular shaft  103 . Outside diameter d 2  of extender shaft  103 ′ is slightly smaller than inside diameter d 1  of perpendicular shaft  103 , so that extender shaft  103 ′ can be fitted into shaft  103 . The axes of both shafts would then be substantially co-axial. Also, the insertion technique can involve a rotational offset of shaft  103 ′ relative to shaft  103 , to permit buttons  301  and  302  to bypass certain of the holes during insertion until the appropriate hole is matched with the appropriate button whereupon a twisting action can result in the appropriate button snapping into the appropriate hole. 
         [0024]    Extender shaft  103 ′ can be inserted into shaft  103  by a minimum overlap distance d 3  represented by button  301  snapping into aperture  203 . This would lock both shafts together and the locked shafts would provide a fixed distance in their co-axial direction. Furthermore, both shafts would then be constrained to rotate together. Minimum distance d 3  can be selected to be whatever minimum distance is needed to provide sufficient rigidity to both shafts, and a reasonable minimal overlap between the two shafts may be a 50% overlap, where extender shaft  103 ′ penetrates into shaft  103  by 50% of the length of shaft  103  and by 50% of the length of shaft  103 ′. This would occur when the lengths of shafts  103  and  103 ′ are equal. Extender shaft  103 ′ can penetrate into shaft  103  by more than that amount by having button  301  snap into aperture  202 , or even into aperture  201 . 
         [0025]    Button  302  is provided and is displaced from button  301  by a distance that is other than the distance between holes  201  and  202  or between holes  202  and  203 . Therefore, if button  302  is inserted into one of holes  201 ,  202  or  203  instead of button  301 , that connection offers additional variety to the distance between screw blades if desired, which would be the case if length L of  FIG. 1  is not standard in a particular application. Further, there can be a large number of buttons, more than the two shown, set apart from each other at progressively smaller distances which, in combination with apertures  201 ,  202  and  203  would allow for an even larger variety of selectable distances for length L. There can also be more apertures that the three shown and they can be set apart from each other at progressively smaller distances, also offering a variety of selectable distances for length L. 
         [0026]    The description of shaft connection and operation provided in the preceding paragraphs with respect to perpendicular shaft  103  and extender shaft  103 ′ are directly applicable to connection and operation with respect to perpendicular shaft  102  and extender shaft  102 ′, in a mirror-image context. Therefore, that detail won&#39;t be repeated for perpendicular shaft  102 . However, it should be appreciated that locations of various holes and spring-loaded buttons used in perpendicular shaft  102  and extender shaft  102 ′ need not be equal to, nor mirror-image symmetrical with respect to, locations in perpendicular shaft  103  and extender shaft  103 ′. In fact, inequality and asymmetry in this respect is advantageous, because that would provide a wider variety of possible lengths L (L shown in  FIG. 1 ), including default standard lengths, as a result. 
         [0027]    Returning to  FIG. 1 , extender shafts  102 ′ and  103 ′ are shown connected to gears in gear boxes  108  and  107 , respectively. As an alternative embodiment, extender shafts  102 ′ and  103 ′ could be configured to interconnect with additional shafts (not shown) similar to  102  and  103  which, in turn, would be the shafts that connect directly to the gears. In other words, the right hand side of  FIG. 1  would reflect perpendicular arm  103  snap-connected to extender arm  103 ′ which, in turn, would be snap-connected to another co-axial perpendicular arm (not shown, but having the same inner diameter d 1  as that of arm  103 ) that would, in turn, connect directly to a gear in gear box  107 . And, the left hand side of  FIG. 1  would reflect perpendicular arm  102  snap-connected to extender arm  102 ′ which, in turn, would be snap-connected to another co-axial perpendicular arm (not shown, but having the same inner diameter d 1  as that of arm  102 ) that would, in turn, connect directly to a gear in gear box  108 . There could be a large number of these additional shafts of varying lengths, thereby providing a wide variety of lengths L. 
         [0028]      FIG. 4  is an exemplary schematic diagram of a top view of a portion of the rigid T sleeve support  104  shown in  FIG. 1 . Shaft  101  is shown with handle  105  removed. T support  104  has mirror image halves  104   a  and  104   b , including truss structure  104   a ′ and  104   b ′, which congruently fit together along seam  401 . The mirror image halves and truss structure ( 104   a ,  104   a ′ and  104   b ,  104   b ′) can snap and lock together, and can be readily taken apart as may be needed. Bracing structure  104   a ′ and  104   b ′ is shown in this top view as solid structure that can operate as a truss to offer additional rigidity to T sleeve  104 . The T sleeve including its truss structure can be made from metal or hard plastic. And the various rotatable shafts, gears, gear boxes, truss supports and any other necessary structure can all be made from metal or hard plastic. 
         [0029]      FIG. 5  is an exemplary schematic diagram of a second embodiment, namely a telescoping equivalent of the structure depicted in  FIGS. 2 and 3 . Instead of the snap-together extenders, a telescoping extender can be used, as shown in  FIG. 5 . Component  501  slides (telescopes) into component  502  which, in turn, slides into component  503 . This operates similarly to how a radio antenna might be manually adjusted, to telescope into a greater or smaller effective length. As before, sufficient minimum overlap, per component, would have to be maintained to ensure sufficient overall rigidity. This can be accomplished by having “stops” (not shown in this Fig. but shown in  FIGS. 6 and 7 ) built into the telescoping components at predetermined locations to ensure a particular overlap, e.g., 50% overlap, if that were the overlap desired. This telescoping embodiment could also use spring loaded snap buttons with their complementary apertures to add axial-length certainty and rotational rigidity, as discussed above. Or, this embodiment can be held in an axially-directed fixed position by a tight fit between telescoping components, while the rotational integrity can be achieved by the above noted spring loaded snap buttons or by a tongue and groove technique described below. 
         [0030]      FIG. 6  is a vertical cross sectional view of a portion of the telescoping structure of  FIG. 5 , and more specifically of the telescoping component  503  portion. Cylindrical telescoping component  502  slides within component  503 . The components may be cylindrical or have a different cross section, such as, e.g., square or rectangular. A square or rectangular cross-section could avoid the need of an interlocking tongue and groove design which is built into this second embodiment, as follows. 
         [0031]    Tabs or protrusions  601   a  and  601   b , at opposite sides of component  502  and on one end of component  502 , extend radially from the outer surface of component  502  and slide within grooves or channels  603   a  and  603   b  formed in the wall of cylindrical-component  503 . The thickness of that wall is shown as “T” and the groove or channel has a depth of approximately T/2. Tabs  601   a  and  601   b  make physical contact with limit stops  602   a  and  602   b , respectively, when component  502  penetrates component  503  to its maximum allowed extent. Stops  602   a  and  602   b  prevent cylindrical component  502  from penetrating any further into cylindrical component  503 , beyond stops  602   a  and  602   b . This limit on penetration ensures sufficient component overlap and, therefore, sufficient rigidity of the perpendicular shaft. 
         [0032]    Component  502  also has grooves or channels formed in its wall, configured to accept different tabs (not shown) located on cylindrical component  501  (not shown in  FIG. 6 ). Channel  604  is one of those channels formed in the wall thickness of component  502  and is shown as being angularly displaced from channels  603   a  and  603   b  by approximately 90 degrees. There is another channel (not shown) formed in the wall thickness of component  502 , directly opposite from channel  604 , similar to the arrangement of channels  603   a  and  603   b  in component  503 , but offset from them by approximately 90 degrees. A tab located on component  501  (not shown) would slide within channel  604 , and a similar tab directly opposite that tab on component  501  would slide within the other channel directly opposite from channel  604 . These interlocks (tabs and grooves) would then constrain the combined shaft comprised of components  501 ,  502  and  503  to rotate together, and the limit-stops ( 602   a ,  602   b , etc.) limit its overall length. 
         [0033]    Further, if the fit between the three telescoping components was sufficiently tight, then the need for button connections to fix length in the axial direction could be eliminated. After length L is set manually, the forces on rotatable perpendicular combined shaft  501 / 502 / 503  are torsional or rotational rather than axial, wherefore the button constraints to fix length could be avoided. Cylindrical components  503  and  502 , as well as cylindrical component  501  (not shown in this Fig.) together comprise a complete perpendicular shaft described above. The foregoing describes one of the two disclosed perpendicular shafts, and a similar configuration and arrangement of tabs and grooves can be used on the opposite perpendicular shaft so that they both function and operate in the same manner. Or, the opposite perpendicular shaft can be of fixed length, where all length L variation is obtained via only one of the two perpendicular shafts. 
         [0034]      FIG. 7  is a schematic drawing of an end view of only component  503 , looking at it from the left hand side of  FIG. 6 . Component  503  is cylindrical with wall thickness T. Channels or grooves  603   a  and  603   b  are formed in wall thickness T, directly opposite each other. Component  503  has inner wall  701  bounding a cylindrical space into which component  502  (not shown to enhance clarity of illustration) may be inserted. Component  502  may be inserted with only one of two orientations, where the tabs on component  502  must fit into grooves  603   a  and  603   b . If the grooves  603   a  and  603   b  were not directly opposite each other, in a particular configuration, then there would be only one keying orientation possible for component  502 . 
         [0035]    If square or rectangular perpendicular shafts were used instead of cylindrical perpendicular shafts where, e.g., a square exterior for component  502  fit matingly into a square aperture within component  503 , then the keying mechanisms (tab and groove) would not be needed. In other words, a square outer shaft configuration for shaft  502  fitting into a square inner shaft configuration for shaft  503  would be constrained to rotate together. 
         [0036]    In the preceding specification, various preferred embodiments have been described with reference to the accompanying drawings. It will, however, be evident that various modifications and changes may be made thereto, and additional embodiments may be implemented, without departing from the broader scope of the invention as set forth in the claims that follow. For example, in the disclosed embodiments, only two screws are shown, but the claimed apparatus and methodology are not limited to operating with only two screws - three or more screws could be simultaneously operated upon in embodiments intended to be embraced by the appended claims. 
         [0037]    For another alternative embodiment, in the above-described third gear box, there could be an additional mesh gear to reverse the rotational motion of its associated parallel shaft from the direction it would have otherwise assumed without operation of the additional mesh gear. In this manner, using the two screw embodiment as an example, one screw could be rotated clockwise while the other screw could simultaneously be rotated counterclockwise. 
         [0038]    For yet another alternative embodiment, the structure of  FIGS. 2 and 3 , using spring-loaded buttons that snap into holes to hold the perpendicular shafts rigid, could be combined with the structure of  FIGS. 5 ,  6  and  7 , using a telescopic structure. In other words, telescopic segment  502  could snap together with telescopic segment  503  at, e.g., standard lengths L while telescopic segment  501  could operate as discussed with respect to  FIGS. 5 ,  6 , and  7 , thereby offering a flexibility to “tune” the length L to mate with an un-conventional distance between two screws, as may be needed. 
         [0039]    The present invention is thus not to be interpreted as being limited to particular extender shafts or particular numbers of gear boxes or particular numbers of perpendicular shafts. Therefore, the specification and drawings are to be regarded in an illustrative rather than restrictive sense.