Patent Publication Number: US-2015062807-A1

Title: Computing device cover

Description:
TECHNICAL FIELD 
     This disclosure relates generally to techniques for forming a cover of a computing device. More specifically, the disclosure describes techniques for increasing platform stiffness with protrusions and recesses in the cover of a computing device. 
     BACKGROUND 
     With the fast growth of computing devices, lighter, thinner computing devices are increasingly preferred by users. Platform stiffness may affect usability, reliability, and perceived quality while also preventing stress of various components. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a diagram of a computing device illustrating torsional twisting. 
         FIG. 2  is a top view of protrusions and recesses of computing device covers. 
         FIGS. 3A-3C  are top views of protrusions and recesses in various shapes. 
         FIG. 4  is a peripheral view of a bottom cover and a top cover being coupled by the protrusions and recesses of each. 
         FIG. 5  is a bar graph illustrating an increase of torsional stiffness due to the protrusions and recesses of the bottom and top covers. 
         FIG. 6  is a block diagram illustrating a method of forming a bottom cover and a top cover with protrusions and recesses to increase platform stiffness. 
     
    
    
     DETAILED DESCRIPTION 
     The subject matter disclosed herein relates to techniques for increasing platform stiffness. A computing device may be configured having a bottom cover and a top cover. The bottom cover may include protrusions received at recesses of the top cover. In the embodiments described herein, a top cover and a bottom cover may be interleaved by the protrusions and recesses of the top and bottom covers, thereby increasing platform stiffness. Method and systems related to increasing stiffness of the platform of the computing device, while avoiding an increase of mass of the platform is described herein. 
       FIG. 1  is a diagram of a computing device illustrating torsional twisting. The computing device  100  includes a top cover  102  and a bottom cover  104 . The computing device may include corners. In some scenarios, force may be applied to one corner as illustrated by the arrow  106 , while other corners may be held stable as illustrated by the triangles  108 ,  110 , and  112 . In this scenario, the computing device may experience twisting, or torsional stress. In some cases, torsional stress may cause the top cover  102  to slide in relation to the bottom cover  104 . A computing device that is more easily twisted may be unreliable in terms of component operation, usability, and perceived quality. The embodiments described herein include a computing device platform with increased stiffness such that the platform resists torsional stress. Further, the embodiments described herein include an apparatus for increasing torsional stiffness without requiring an increase in the number of screws used to hold the covers of the computing device together. 
       FIG. 2  is a top view of protrusions and recesses of computing device covers. As illustrated in  FIG. 2 , the recesses  202  of a top cover  204  may be configured to receive the protrusions  206  of the bottom cover  208 . The recesses  202  and the protrusions  206  are a slide reduction mechanism configured to reduce sliding between the top cover  204  and the bottom cover  208 . 
     The protrusions  206  are formed as a pattern along the periphery of a first portion, such as the bottom cover  208 , of the computing device. A “pattern,” as referred to herein, is a series of protrusions extending along the periphery of a portion, such as the bottom cover  208 . In embodiments, the pattern is implemented at the bottom cover  208 , and a mirrored pattern is implemented as recesses of the top cover  204 . In embodiments, the recesses may be disposed on the bottom cover  208  while the protrusions are disposed on the top cover  204 , rather than protrusions being exclusively at the bottom cover  208  and recesses exclusively at the top cover  204 . 
     A “cover,” as referred to herein, is a component of a computing device configured to house other components of a computing device such as a processing device, a memory device, a storage device, and the like. A cover may be an outer housing, such as an outer skin. In embodiments, a cover may be a sub-frame, such as a chassis, configured as a platform sub-structure upon which other components of the computing device may be housed or attached. For example, the top cover  204  of  FIG. 2  may be a sub-frame configured to be coupled to a display, such as a touchscreen of a tablet computer. As another example, the bottom cover  208  may be a component configured to house a tablet computer. 
     In some embodiments, the protrusions  206  of the bottom cover  208  include at least two 90 degree angle transitions as illustrated in  FIG. 2 . The protrusions  206  are configured to be received at the recesses  202  of the top cover  204 , and the recesses  202  include at least two 90 degree angle transitions to receive the protrusions  206  of the bottom cover  208 . In embodiments, the 90 degree angle transitions of each of the protrusions  206  and the recesses  202  prevent sliding as indicated by the arrows in the dashed circle  210  between the bottom cover  208  and the top cover  204 . The reception of the protrusions  206  at the recesses  202  may increase shear load capacity between the top cover  204  and the bottom cover  208 . 
     The “shear load capacity,” as referred to herein, is the strength of a material or component against a type of yield where the material or component fails in shear due to a shear load. A shear load is a force that tends to produce a sliding failure on a material along a plane that is parallel to the direction of the force. For example, a shear load may be placed on the bottom cover  208  when a user holds the computing device by one corner resulting in a shear load being between the bottom cover  208  and the top cover  204 . The 90 degree angles of the recesses  202  and the protrusions  206  may reduce sliding  210  between the top cover  204  and the bottom cover  208  when the protrusions  206  are received at the recesses  202 . In embodiments, the increase of shear load capacity reduces relatively sliding between the top cover  204  and the bottom cover  208  and results in an increase of overall torsional stiffness of the computing device. 
     Although the protrusions  206  and the recesses  202  are illustrated in  FIG. 2  as being rectangular in shape, the protrusions  206  and recesses  202  may be implemented as shapes other than rectangular. For example, the protrusions  206  and recesses  202  may be trapezoidal, oval, semi-circular, or any other suitable shape such that shear load capacity is increased between the bottom cover  206  and the top cover  202 . 
       FIGS. 3A-3C  are top views of protrusions and recesses of in various shapes.  FIG. 3A  illustrates that the protrusions  206  may be semi-circular shape and received by recesses  202  as indicated by the arrows  302 .  FIG. 3B  illustrates that the protrusions  206  may be semi-diamond shape and received by the recesses  202  as indicated by the arrows  304 .  FIG. 3C  illustrates that the protrusions  206  may be semi-trapezoidal in shape and received by recesses  202  as indicated by the arrows  306 . Other shapes not illustrated in  FIGS. 3A-3C  may be implemented so long as sliding between the bottom cover and the top cover is reduced when the protrusions  208  are received by the recesses  208 . 
       FIG. 4  is a peripheral view of a bottom cover and a top cover being coupled by the protrusions and recesses of each. As illustrated in  FIG. 4 , the protrusions  208  of the bottom cover  208  may be received by the recesses  202  of the top cover  204  as indicated by the dashed circle  402 . The protrusions  208  received by the recesses  202  reduce sliding of the bottom cover with respect to the top cover, as indicated by the arrows  404 . 
     In embodiments, the bottom cover  208  may include side walls. As illustrated in  FIG. 4 , the protrusions of the bottom cover  208  may be disposed perpendicular to the side walls of the bottom cover  208 . Although  FIG. 4  illustrates that the protrusions of the bottom cover are formed perpendicular to the side walls of the bottom cover  208 , the protrusions may be in line with the side walls and extend vertically from the periphery of the side walls of the bottom cover  208 . 
     In embodiments, the top cover  204  may be a sub-frame, or an intermediate structural member behind a front cover of the computing device as discussed above in reference to  FIG. 2 . The sub-frame of the top cover  204  may be configured to receive additional components such as a display of an all-in-one (AIO) device. An AIO device, as referred to herein, is a computing device configured to house a display as well as computing components including a processor within a housing. The top cover  204  and bottom cover  208  may be components of an AIO device housing. The embodiments described herein may be implemented as a form factor reference design (FFRD). For example, the protrusions of a bottom cover being received at recesses of a top cover may be implemented in a tablet computing device as a FFRD implementation. 
     The protrusions and recesses may be large enough to provide an increased torsional stiffness. In embodiments, the increase of torsional stiffness may be a function of the size of the protrusion from the bottom cover  206 . For example, the protrusion of the bottom cover  208  may be 2.5 millimeters as indicated by  406  in  FIG. 4 . Likewise, the recess of the top cover  202  may be at least 2.5 millimeters such that it may receive a protrusion of 2.5 millimeters. 
       FIG. 5  is a bar graph illustrating an increase of torsional stiffness due to the protrusions and recesses of the bottom and top covers. As discussed above in reference to  FIG. 2 , the increase of shear load capacity between the top cover  204  and the bottom cover  208  may result in overall torsional stiffness of the computing device. The bar graph  500  of  FIG. 5  illustrates an increase of torsional stiffness  502  in different implementations of the embodiments discussed herein. Bar  504  shows a torsional stiffness of less than 40 pounds force per inch (lbf/in) when the top cover and bottom cover do not include protrusions and recesses as discussed above in reference to  FIGS. 2 and 3 . Bar  506  shows that the torsional stiffness increases to greater than 120 lbf/in when the top cover and bottom cover do include the protrusions and recesses, relative to the device represented by bar  504 . Bar  508  shows that the torsional stiffness is still above 100 lbf/in when the top cover and bottom cover include protrusions and recesses, even when the thickness of the top cover is reduced to around 1 millimeter thick from more than 2 millimeters thick. Bar  510 , the torsional stiffness is less than 100 lbf/in, yet still more than 80 lbf/in when the top and bottom cover include protrusions and recesses, and even when thickness of the bottom cover is reduced to around 1 millimeter thick the top cover reduced from 2 millimeters thick to 0.5 mm thick. Therefore, a device implementing the techniques described herein may be relatively lighter than a device that does not implement the techniques. 
       FIG. 6  is a block diagram illustrating a method of forming a bottom cover and a top cover with protrusions and recesses to increase platform stiffness. At block  602 , a first portion of a computing device is formed. The protrusions are formed as a pattern along the periphery of the first portion. In embodiments, the first portion is a bottom cover of the computing device. The protrusions may be formed along the periphery of the bottom cover and received at recesses of a second portion, such as a top cover of the computing device. At block  604 , a second portion is formed having recesses configured to receive the protrusions of the bottom cover. As discussed above, the second portion may be a top cover and the recesses of the top cover may be configured to receive the protrusions of the bottom cover. 
     As discusses above, the protrusions are formed along the periphery of the bottom cover. For example, the bottom cover may include a side wall and the protrusions may be formed perpendicular to the side wall of the bottom cover, and at a periphery of the bottom cover. In embodiments, the protrusions may be formed extending vertically from the side wall of the bottom cover. 
     Each protrusion and corresponding recess may be referred to herein as a stiffening element. The torsional stiffness of the computing device may be a function of the number of stiffening elements included in the cover. For example, a bottom cover having only 1 protrusion every 5 inches may result in a relatively less stiff platform for a computing device than a bottom cover having 2 protrusions every 5 inches. By forming the top and bottom covers to include a simple repeating pattern of recesses and protrusions, a large number of stiffening elements may be incorporated into the cover at relatively low cost. For example, in some embodiments, the cover may include 8, 16, 32, 64 or more stiffening elements. In some embodiments, the protrusions and recesses may slide together vertically, radially, or other direction sufficient to prevent sliding between the top cover and the bottom cover. In some embodiments, the techniques described herein enable insertion of interlocking features in a radial motion while a vertical motion (separating bottom from top) is constrained. Thus, a panel may be inserted with interlocking tabs, snapped in place, and very difficult to remove. The techniques described herein may be implemented as a security/tamper proof design where a chassis may be desired to have some level of tamper resistance. 
     In some embodiments, when the angles of protrusions and recesses are normal to the direction of sliding between the top cover and bottom cover then a radial force and a force, such as a camming action, that separates the top and bottom covers vertically may result. Thus, the techniques described herein include bearing surfaces of each of the recesses and/or protrusions are normal to the sliding direction, or with an angle that produces a force that pulls the covers together, as illustrated in  FIGS. 3B and 3C . 
     In embodiments, the protrusions and the recesses are formed having at least two 90 degree angle transitions each. The 90 degree angle transitions may be useful in preventing sliding between the top cover and the bottom cover. Other angles are contemplated by the embodiments discussed herein, and are not limited to 90 degree angle transitions. For example, the protrusions and recesses may include transitions that are more or less than 90 degrees such that sliding between the top cover and the bottom cover is reduced. 
     EXAMPLE 1 
     A method of forming covers of a computing device is described herein. The method may include forming a first portion of a computing device having protrusions, the protrusions formed as a pattern along the periphery of the first portion. A second portion may be formed. The second portion may be formed having recesses to receive the protrusions of the first portion. 
     EXAMPLE 2 
     An apparatus is described herein. The apparatus may include a first portion of a computing device. The first portion includes protrusions formed as a pattern along the periphery of the first portion. The first portion may be a covering means, such as a bottom cover of the computing device, and the apparatus may include a second portion of the computing device, the second portion having recesses to receive the protrusions. Thus, the second portion may be a covering means, such as a top cover of the computing device. The top cover may, in some cases, be configured with recesses to receive the protrusions of the bottom covering means. 
     EXAMPLE 3 
     A computing device is described herein. The computing device may include protrusions at a side wall of a first portion of the computing device. For example, the protrusions may extend perpendicularly from a side wall of a bottom covering means. The protrusions are formed as a pattern along the periphery of the first portion. The computing device may include recesses of a second portion of the computing device, the recesses to receive the protrusion of the first portion. For example, the recesses may be in a covering means, or in a sub-frame of the computing device, and may be configured to receive the protrusions extending from the periphery of the first portion, such as the bottom cover. 
     An embodiment is an implementation or example. Reference in the specification to “an embodiment,” “one embodiment,” “some embodiments,” “various embodiments,” or “other embodiments” means that a particular feature, structure, or characteristic described in connection with the embodiments is included in at least some embodiments, but not necessarily all embodiments, of the present techniques. The various appearances of “an embodiment,” “one embodiment,” or “some embodiments” are not necessarily all referring to the same embodiments. 
     Not all components, features, structures, characteristics, etc. described and illustrated herein need be included in a particular embodiment or embodiments. If the specification states a component, feature, structure, or characteristic “may”, “might”, “can” or “could” be included, for example, that particular component, feature, structure, or characteristic is not required to be included. If the specification or claim refers to “a” or “an” element, that does not mean there is only one of the element. If the specification or claims refer to “an additional” element, that does not preclude there being more than one of the additional element. 
     It is to be noted that, although some embodiments have been described in reference to particular implementations, other implementations are possible according to some embodiments. Additionally, the arrangement and/or order of circuit elements or other features illustrated in the drawings and/or described herein need not be arranged in the particular way illustrated and described. Many other arrangements are possible according to some embodiments. 
     In each system shown in a figure, the elements in some cases may each have a same reference number or a different reference number to suggest that the elements represented could be different and/or similar. However, an element may be flexible enough to have different implementations and work with some or all of the systems shown or described herein. The various elements shown in the figures may be the same or different. Which one is referred to as a first element and which is called a second element is arbitrary. 
     It is to be understood that specifics in the aforementioned examples may be used anywhere in one or more embodiments. For instance, all optional features of the computing device described above may also be implemented with respect to either of the methods or the computer-readable medium described herein. Furthermore, although flow diagrams and/or state diagrams may have been used herein to describe embodiments, the techniques are not limited to those diagrams or to corresponding descriptions herein. For example, flow need not move through each illustrated box or state or in exactly the same order as illustrated and described herein. 
     The present techniques are not restricted to the particular details listed herein. Indeed, those skilled in the art having the benefit of this disclosure will appreciate that many other variations from the foregoing description and drawings may be made within the scope of the present techniques. Accordingly, it is the following claims including any amendments thereto that define the scope of the present techniques.