Abstract:
A tilt mechanism of the type for interconnecting two members in a manner such that the two members may be moved and placed in various positions in relation to one another. The tilt mechanism comprising: an outer mandrel connected to a first member; an intermediate mandrel connected to a second member, the intermediate mandrel being movably disposed about a portion of the outer mandrel; an inner mandrel in functional connection with the outer and intermediate mandrel; a first spring functionally connected about a portion of the outer mandrel and the inner mandrel in a manner such that the first spring resists movement when moved in a first direction and releases tension when moved in a second direction; and a second spring functionally connected about a portion of the intermediate mandrel and the inner mandrel in a manner such that the second spring resists movement when moved in a second direction and releases tension when moved in a first direction.

Description:
FIELD OF THE INVENTION 
     The present invention relates generally to a mechanism for movable interconnecting two objects and more specifically to a tilt mechanism which utilizes an overrunning spring clutch type assembly that allows for angular rotation of the objects in relation to one another and allows placement of the objects in variable static positions based on the operator&#39;s requirements. 
     BACKGROUND OF THE INVENTION 
     Apparatuses such as laptop computers, handheld computers, touch screen systems, and other electronic devices typically include a base with keys and a cover rotationally coupled to the base. These devices are designed for portability and convenience wherein the cover serves both as protection and as a functional portion of the device. The cover often includes a liquid crystal display (LCD) or plasma display which is functionally connected to the terminal&#39;s memory to display information. The cover may be pivoted from a closed position in which it is folded against the base for storage or transport and to an open position for operation. In the open position the cover is pivoted to a position so that the user can effectively see the screen. The position of the screen will depend on factors such as, the height of the user, position of the user in relation to the device, and lighting conditions. These factors in conjunction with the portable nature of the device result in repetitive movement of the cover in relation to the base. This repetitive movement of the cover results in wear of the prior art connecting mechanisms, such as compressed friction washers, and failure of the mechanism to maintain the cover in a set position. This failure of stability of placement of the cover is pronounced when the cover includes a touch screen wherein force is applied against the screen and cover when in use. 
     It would be a benefit therefore to have a tilt mechanism that movably interconnects two members and allows the members to be repetitively moved and set in a plurality of positions relative to one another. It would be a further benefit to have a tilt mechanism that has sufficient strength to retain one member at a selected position even when that position is not perpendicular to the attached member. It would also be a benefit to have a tilt mechanism that permits variability in setting the rotational position of one member to the other member. It would be a further benefit to have a tilt mechanism that allows for a first amount of force to be utilized to move a member in a first direction and a second amount of force to be utilized to move a member in a second direction wherein the first and second force may be different which is particularly beneficial in touch screen systems. 
     SUMMARY OF THE INVENTION 
     It is thus an object of the present invention to provide a tilt mechanism that allows one member to be repetitively moved and set in a plurality of positions relative to each other. 
     It is a further object to provide a tilt mechanism that has sufficient strength to retain one member in a selected position even when that position is offset from vertical. 
     It is a further object to provide a tilt mechanism that permits variability in the setting the rotational position of one member to the attached member. 
     It is a further object to provide a tilt mechanism that allows for a first amount of force to be utilized to move a member in a first direction and a second amount of force to be utilized to move a member in a second direction, wherein the first and second force may be different. 
     Accordingly, a tilt mechanism of the type for interconnecting two members in a manner such that the two members may be moved and placed in various positions in relation to one another. The tilt mechanism comprising: an outer mandrel connected to a first member; an intermediate mandrel connected to a second member, the intermediate mandrel being movably disposed about a portion of the outer mandrel; an inner mandrel in functional connection with the outer and intermediate mandrel; a first spring functionally connected about a portion of the outer mandrel and the inner mandrel in a manner such that the first spring resists movement when moved in a first direction and releases tension when moved in a second direction; and a second spring functionally connected about a portion of the intermediate mandrel and the inner mandrel in a manner such that the second spring resists movement when moved in a second direction and releases tension when moved in a first direction. 
     The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that the detailed description of the invention that follows may be better understood. Additional features and advantages of the invention described hereinafter form the subject of the claims of the invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 is a cross-sectional view of the tilt mechanism of the present invention. 
     FIG. 2 is an exploded, side view of the tilt mechanism of the present invention. 
     FIG. 3 is a perspective view of a touch screen device utilizing a tilt mechanism of the present invention. 
    
    
     DETAILED DESCRIPTION 
     Refer now to the drawings wherein depicted elements are not necessarily shown to scale and wherein like or similar elements are designated by the same reference numeral through the several figures. 
     FIG. 1 is a cross-sectional view of the tilt mechanism of the present invention generally designated by the numeral  10 . Tilt mechanism  10  includes an outer mandrel  12 , an intermediate mandrel  14 , an inner mandrel  16 , a first spring  18 , and a second spring  20 . Tilt mechanism  10  is functionally connected between a first member  22  and a second member  24  in a manner such that first and second members  22 ,  24  can be angularly moved in relation to each other and maintained in a plurality of positions. Members  22  and  24  may be brackets that are connected to other portions of a device. An example would be first member  22  being a bracket connected to a keyboard or base of a portable computer and second member  24  being a bracket connected to the display portion of a portable computer. Although only one tilt mechanism  10  is shown in the embodiment, it should be recognized that more than one tilt mechanism  10  may be utilized, for example two tilt mechanisms  10  connecting a keyboard with a display unit. It should be readily recognized that tilt mechanism  10  may be utilized for connecting many devices wherein at least two objects are movably interconnected and wherein it is desired to maintain the two objects in various angular positions in relation to each other. 
     Outer mandrel  12  may be constructed of any suitable material such as a hard plastic for use in a portable computer. Outer mandrel  12  has an anterior portion  26  for connecting to first member  22 . First member  22  is fixedly connected to anterior portion  26  by adhesive, chemical welding, welding, retaining rings or any other manner which maintains outer mandrel  12  in a fixed position in relation to first member  22 . Outer mandrel  12  forms an expanded diameter portion  28  adjacent to anterior portion  26 . Adjacent to expanded portion  28  is a friction portion  30  which has a smaller diameter than expanded portion  28 . Extending from friction portion  30  is an elongated extension  32 . Elongated extension  32  may form an internal bore for disposing a locking element such as a screw. 
     Intermediate mandrel  14  forms an internal bore  34  therethrough. Internal bore  34  has an inside diameter approximate the outer diameter of expanded portion  28  of outer mandrel  12  so that expanded section  28  may be disposed therein. Intermediate mandrel  14  is adapted to rotate about outer mandrel  12 . 
     Second member  24  is fixedly connected to a first end  36  of intermediate member  14 . Second member  24  and intermediate member  14  may be connected with adhesive, chemical welding, welding, retaining rings or any other manner which maintains intermediate member  14  in a fixed position in relation to second member  24 . When second member  24  is moved in relation to first member  22 , second member  24  and intermediate mandrel  14  rotate about outer mandrel  12 . 
     Intermediate mandrel  14  further includes a recessed outer diameter section  38  distal from first end  36 . Recessed section  38  has a smaller outer diameter than the body  39  of intermediate mandrel  14  so as to allow the functional placement of second spring  20 . 
     Inner mandrel  16  forms a pathway  40  therethrough approximate the longitudinal axis of inner mandrel  16 . Pathway  40  is sized to dispose elongated extension  32  of outer mandrel  12  therein. Inner mandrel  16  may be rotatably connected to outer mandrel  12  by a retaining screw  52  or the like as shown in FIG.  2 . 
     Inner mandrel  16  includes a first section  42 , second section  44 , and a third section  46  which are formed in stair step fashion along the exterior thereof. First section  42  has an outer diameter approximate the outer diameter of body  39  of intermediate mandrel  14 . Second section  44  has an outside diameter less than that of first section  42  and approximate the outside diameter of recessed portion  38  of intermediate mandrel  14 . Third section  46  has an outside diameter smaller than second section  44  and approximate the outside diameter of friction section  30  of outer mandrel  12 . 
     When mandrels  12 ,  14 , and  16  are functionally connected, a first spring cavity  48  and a second spring cavity  50  are formed. Each cavity  48  and  50  are adapted for holding a spring to provide resistance to the movement of sections  22  and  24  in relation to each other. 
     First spring cavity  48  is defined between second section  44  of inner mandrel  16  and expanded portion  28  of outer mandrel  12 , along the outside diameter of third section  46  of mandrel  16  and the outside diameter of friction section  30  of mandrel  12 , and along the inside diameter of bore  34  of mandrel  14 . First spring cavity  48  is adapted to hold first spring  18  about friction section  30  of outer mandrel  12  and third section  46  of inner mandrel  16 . 
     Second spring cavity  50  is defined between body  39  of mandrel  14  and first section  42  of mandrel  16  along the outside diameter of second section  44  of mandrel  16  and the outside diameter of recessed portion  38  of mandrel  14 . Second spring cavity  50  is adapted to hold second spring  20  about recessed portion  38  of mandrel  14  and second section  44  of mandrel  16 . 
     FIG. 2 is an exploded, side view of tilt mechanism  10  of the present invention. FIG. 2 is representative of construction of tilt mechanism  10 . As shown, first member  22  is fixedly connected to outer mandrel  12 . Second member  24  is fixedly connected to intermediate mandrel  14  at first end  36 . 
     First spring  18  is a helical spring desirably having a inside diameter less than the outside diameter of friction section  30  of mandrel  12  and the outside diameter of third section  46  of mandrel  16 . First spring  18  is disposed about friction section  30  of mandrel  12 . 
     Intermediate mandrel  14  is placed so that the majority portion of mandrel  12  is disposed within bore  34  of mandrel  14 . Outer mandrel  12  is disposed within bore  34  of intermediate mandrel  14  in a manner such that mandrel  14  may rotate about mandrel  12 . 
     Second spring  20  is a helical spring desirably having an inside diameter less than the outside diameter of recessed portion  38  of mandrel  14  and second portion  44  of mandrel  16 . Second spring  20  is disposed about recessed portion  38  of mandrel  14 . 
     Inner mandrel  16  is attached by disposing elongated extension  32  of mandrel  12  into pathway  40  of mandrel  16 . Inner mandrel  16  is moved towards mandrel  12  so that third section  46  is inserted within first spring  18  and second section  44  is disposed within second spring  20 . Inner mandrel  16  is rotatably connected to outer mandrel  12  such as by, but not limited to, spring  18 . Screw  52  prevents mandrel  16  from gradually creeping away from mandrel  12  during rotation due to the spring force. 
     First spring  18  is oriented in a direction so as to tighten about third section  46  of inner mandrel  16  and friction section  30  of outer mandrel  12  when moved in a first direction and unwind when moved in a second direction. Second spring  20  is oriented in a direction so as to tighten about recessed portion  38  of intermediate mandrel  14  and second portion  44  of inner mandrel  16  when moved in a second direction and unwind when moved in a first direction. 
     FIG. 3 is a perspective view of a touch screen device  21  utilizing tilt mechanism  10  of the present invention. Device  21  is a touch screen device such as used in a retail store. Device  21  includes a touch screen  24  that allows the user to select options by contacting the screen with a finger or wand. Touch screen  24  is movably connected to a base  22  which may include a data processing system having a central processing unit (CPU), such as a conventional microprocessor, and a number of other units interconnected via a system bus. The data processing system includes a random access memory (RAM) and a read only memory (ROM). The system may include an I/O adapter for connecting peripheral devices such as disk units and tape drives to the bus, a user interface adapter for connecting a keyboard, a mouse and/or other user interface devices such as a touch screen  24  or other display device to the bus, a communication adapter for connecting the data processing system to a data processing network. 
     In the application as shown in FIG. 3, tilt mechanism  10  requires a greater force to move touch screen  24  in the direction shown by the letter “A” to resist movement of screen  24  when in use than the force required to move screen  24  in the direction indicated by “B.” 
     Use of tilt mechanism  10  of the present invention is described with reference to FIGS. 1 through 3. Tilt mechanism  10  is described in relation to use with a touch screen computer wherein first member  22  is a base that may include a CPU and a keyboard, and second member  24  may be a touch screen display unit. One and desirably two tilt mechanisms  10  are utilized to interconnect first member  22  and second member  24 . In typical operation second member  24  will be at an angle relative to first member  22 . Depending on the user of the device and environmental conditions it may be desired to place and maintain second member  24  at any number of angular positions from first member  22 . It should also be considered that second member  24  is a weight bearing member and may have forces applied to it during use such as in touch screen systems. In situations such as with a touch screen it is very beneficial to have a tilt mechanism  10  that allows movement of the members within reference to each other while resisting movement when the touch screen is being used. For example, tilt mechanism resisting movement when a force is applied in a direction A and easily moved when a force is applied in the direction B. 
     When second member  24  is moved in a first direction, first spring  18  tightens about mandrels  12  and  16  and second spring  20  unwinds. When second member  24  is moved in a second direction, first spring  18  unwinds and second spring  20  tightens about mandrels  14  and  16 . Tilt mechanism  10  is, in effect, an overrunning spring clutch that is designed to slip in either direction, but at different values of applied torque. By altering the spring constants between spring  18  and  20 , a force may be applied to second member  24 , such as in a touch screen application, without excessive movement of second member  24  while still allowing desired movement and variable placement of second member  24 . 
     Although the present invention and its advantages have been described in detail, it should be understood that various changes, substitutions and alterations can be made herein without departing from the spirit and scope of the invention as defined by the appended claims. For example, various modes and material of construction may be utilized, various orientation of springs and spring constants, manner of connection of elements, and order of connection of elements may be altered without departing from the spirit and scope of the invention as claimed.