Patent Publication Number: US-11019920-B2

Title: Electrically-lifted computer desk and office desk thereof

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 15/333,207, filed Oct. 25, 2016, which claims priority to Chinese Patent Application Ser. No. CN201621074710X, filed Sep. 23, 2016, both of which are hereby incorporated by reference in their entirety. 
    
    
     FIELD OF THE INVENTION 
     The invention relates generally to an electrically-lifted desk, and more specifically to an electrically-lifted desk that can be lifted stably with low noise and great bearing power. The invention also generally relates to an electrically-lifted desk having safety-enhancing features. 
     BACKGROUND OF THE INVENTION 
     With digital homes becoming more common, the household life of people is undergoing enormous changes, wherein the incorporation of digital automation design in modern digital homes is becoming the most outstanding advantage. In a household environment, the desk has been incorporated into human lives with multiple functions. On the current stage, the desk is generally used only as a dining table, a computer desk, a study desk, or the like. Therefore, the functionality of the desk is limited at present, and cannot satisfy the multi-purpose requirements. 
     In order to solve the above-mentioned problem, the Chinese patent CN 102599728A discloses a motor-operated lifting desktop device comprising a lifting desktop. The lifting desktop can be lifted upwards or folded downwards under the drive of the motor device. This lifting desktop device may be suitable for use together with various computer desks, school desks, tea tables, and the like for placing a keyboard and a mouse. However, the lifting desktop device has several problems in use. First, the lifting desktop device cannot be used separately, but can only be used together with a support platform. Second, the structural design is unreasonable: the adoption of two screw rods and nuts combined with a plurality of pivot joint points cause instability when in operation and multiple fault points. Third, the lifting desktop device has limited load bearing capacity: when a certain pressure is applied on the lifting desktop, the whole lifting desktop device will swing front and back, left and right. 
     SUMMARY OF THE INVENTION 
     According to an embodiment, a desk can include a bottom plate; a face plate movably coupled to the bottom plate by one or more support members; a motor configured to selectively move the face plate upward and downward with respect to the bottom plate; and a control mechanism. The control mechanism can include a first sensor device coupled to an upper surface of the bottom plate, the first sensor device having one or more first optical sensors; and a second sensor device aligned parallel to the first sensor device and coupled to a lower surface of the face plate, the second sensor device having one or more second optical sensors in communication with the one or more first optical sensors. The control mechanism is configured to stop the motor from moving the face plate in response to an object between the first sensor device and the second sensor device. 
     According to an embodiment, a method for stopping movement of a face plate of a desk with respect to a bottom plate of the desk can include transmitting an optical signal between one or more first optical sensors aligned along an edge of the face plate, and one or more second optical sensors located on the bottom plate; selectively moving the face plate upward or downward with respect to the bottom plate using a motor; and stopping movement of the face plate by the motor when an object at least partially blocks the optical signal transmitted between the one or more first sensors and the one or more second sensors. 
     According to an embodiment, a desk can include a bottom plate; a face plate movably coupled to the bottom plate by one or more support members; a motor adapted to selectively move the face plate with respect to the bottom plate between a lowered position and a raised position; and a lift-assist spring coupled to the one or more support members, wherein the lift-assist spring is compressed when the face plate is in the lowered position, and the lift-assist spring is extended when the face plate is in the raised position. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a rear-side perspective view of a desk of an embodiment of the invention. 
         FIG. 2  is a front-side perspective view of the embodiment in  FIG. 1 . 
         FIG. 3  is another front-side perspective view of the embodiment in  FIG. 1 . 
         FIG. 4  is a rear-side perspective view of the embodiment in  FIG. 1 , shown in a folded or lowered state. 
         FIG. 5  is a front-side perspective view of another embodiment of the invention. 
         FIG. 6  is a front-side perspective view of the embodiment in  FIG. 5 , shown in a folded or lowered state. 
         FIG. 7  is a partial, perspective view of a desk of another embodiment of the invention, shown with the face plate removed. 
         FIG. 8  is an enlarged perspective view of a portion of the embodiment of  FIG. 7 . 
         FIG. 9  is a side-perspective view of a desk of another embodiment of the invention. 
         FIG. 10  is a perspective view of a portion of a desk of another embodiment of the invention. 
         FIG. 11  is an enlarged, perspective view of a portion of the embodiment of  FIG. 10 . 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to  FIGS. 1-4 , a desk is shown. The desk can be an electrically-lifted computer desk  100 . The electrically-lifted computer desk  100  can comprise a bottom plate  110 , a driving mechanism  120 , an intermediate support member  130 , a first side-support member  140 , a second side-support member  150 , and a face plate  160  (e.g., the desktop). The driving mechanism  120  is fixedly disposed on the bottom plate  110 ; the face plate  160  is fixedly disposed on the first side-support member  140  and the second side-support member  150 ; and the driving mechanism  120  drives the face plate  160  to raise or lower via the intermediate support member  130 , the first side-support member  140 , and the second side-support member  150 . 
     Referring to  FIG. 1 , the driving mechanism  120  comprises a first fixing piece  121 , a second fixing piece  122 , a first guide rod  123 , and a second guide rod  124 . The first fixing piece  121  and the second fixing piece  122  are parallel to each other and are separated by a preset distance. The first guide rod  123  and the second guide rod  124  are parallel to each other, are separated by a preset distance, and form a frame together with the first fixing piece  121  and the second fixing piece  122 . A screw rod  125  is disposed in parallel with the first guide rod  123  at an intermediate position between the first guide rod  123  and the second guide rod  124  of the frame. The two ends of the screw rod are respectively connected with the first fixing piece  121  and the second fixing piece  122 . 
     Still referring to  FIG. 1 , a driving source  126  is disposed at one end of the screw rod  125 . The driving mechanism  120  is fixed on the bottom plate  110  via the first fixing piece  121  and the second fixing piece  122 . The intermediate support member  130  comprises a nut sliding rod seat  131 , a first side-support piece  132 , a second side-support piece  133 , and a transverse link  134 . The nut sliding rod seat  131  is slidable along the first guide rod  123  and the second guide rod  124 , and is in threaded engagement with the screw rod  125  of the driving mechanism  120 . Accordingly, rotation of the screw rod  125  via the driving mechanism  120  provides a reciprocating motion of the nut sliding rod seat  131  along the first guide rod  123  and the second guide rod  124 , depending on the direction of rotation of the driving mechanism  120 . The lower end  1321  of the first side-support piece  132  is pivotally connected with one end of the nut sliding rod seat  131  and the lower end  1331  of the second side-support piece  133  is pivotally connected with the other end of the nut sliding rod seat  131 . The upper ends  1322  and  1332  of the first side-support piece  132  and the second side-support piece  133  are fixedly connected with the transverse link  134 . 
     The screw threads for connecting the nut sliding rod seat  131  with the screw rod  125  can be formed directly in the nut sliding rod seat  131 , or can be formed by embedding a threaded object such as a nut in the nut sliding rod seat  131 . For connecting the nut sliding rod seat  131  to the first guide rod  123  and the second guide rod  124 , a hole can be directly punched in the nut sliding rod seat  131 , or a sliding bush can be embedded after punching a hole in the nut sliding rod seat  131 . 
     The driving source  126  can be driven by a motor  1261 . Two different configurations are possible. One configuration, shown in  FIG. 1 , is that the motor  1261  is directly connected with one end of the screw rod  125  via a speed reducer  1265 . In a second configuration, shown in  FIG. 3 , a first synchronization wheel  1262  is disposed on the output shaft of the speed reducer  1265  of the motor  1261 , a second synchronization wheel  1263  is disposed at one end of the screw rod  125 , and the first synchronization wheel  1262  is connected with the second synchronization wheel  1263  via a synchronization belt  1264 . Alternatively, the driving source  126  can be directly driven by manpower, in which case a rocker (not depicted) for applying force can be disposed at one end of the screw rod  125 . Embodiments of the invention use a frame-shaped driving mechanism and a frame-shaped intermediate support member, and transfer the motive power via the frame-shaped intermediate support member. Therefore, embodiments of the invention can have the advantages of stable lifting, low noise, and great bearing power. 
     Referring to  FIG. 2 , the first side-support member  140  can comprise a third side-support piece  141 , a fourth side-support piece  142 , and a first desktop connecting piece  143  fixedly connected with the face plate  160 . The lower end  1411  of the third side-support piece  141  is pivotally connected with the bottom plate  110 . The upper end  1412  of the third side-support piece  141  is slidably connected with the first desktop connecting piece  143 . The upper end  1421  of the fourth side-support piece  142  is pivotally connected with the first desktop connecting piece  143 . The lower end  1422  of the fourth side-support piece  142  is pivotally connected with the middle part of the third side-support piece  141  and one end of the transverse link  134 . The second side-support member  150  comprises a fifth side-support piece  151 , a sixth side-support piece  152 , and a second desktop connecting piece  153  fixedly connected with the face plate  160 . The lower end  1511  of the fifth side-support piece  151  is pivotally connected with the bottom plate  110 . The upper end  1512  of the fifth side-support piece  151  is slidably connected with the second desktop connecting piece  153 . The upper end  1521  of the sixth side-support piece  152  is pivotally connected with the second desktop connecting piece  153 . The lower end  1522  of the sixth side-support piece  152  is pivotally connected with the middle part of the fifth side-support piece  151  and the other end of the transverse link  134 . The bottom plate  110  is hollowed to form a first flanged edge  111  and a second flanged edge  112 . The lower end of the third side-support piece  141  is pivotally connected with the first flanged edge  111  and the lower end of the fifth side-support piece  151  is pivotally connected with the second flanged edge  112 . 
     With continued reference to  FIG. 2 , the first desktop connecting piece  143  comprises a third flanged edge  1431 . The third flanged edge  1431  is provided with a first guide groove  1432  thereon. A first guide wheel  1413  is disposed at the upper end of the third side-support piece  141 . The third side-support piece  141  is slidably connected with the first guide groove  1432  via the first guide wheel  1413 . The second desktop connecting piece  153  comprises a fourth flanged edge  1531 . The fourth flanged edge  1531  is provided with a second guide groove  1532  thereon. A second guide wheel  1513  is disposed at the upper end of the fifth side-support piece  151 . The fifth side-support piece  151  is slidably connected with the second guide groove  1532  via the second guide wheel  1513 . According to embodiments where any two or more of the aforementioned components are pivotally connected, a bearing or bushing can be assembled at the pivot connecting position, which facilitates the rotation of the members and reduces noise. 
     The desk  100  can further comprise a keyboard plate  170 . The two sides of the keyboard plate  170  are respectively fixedly connected with the first desktop connecting piece  143  and the second desktop connecting piece  153 . Alternatively, the keyboard plate  170  can be slidably connected with the first desktop connecting piece  143  and the second desktop connecting piece  153  via a drawer slide assembly. 
     Referring to  FIGS. 3 and 4 , the desk  100  can be moved back and forth between a lowered, folded position ( FIG. 4 ), a raised, unfolded position ( FIG. 3 ), and a plurality of intermediate positions therebetween. 
     Referring to  FIGS. 5 and 6 , the desk  100  can form part of an office desk  200 . The face plate  160  can be directly replaced with an office desk face plate to form an integrative office desk  200  provided with the electrically-lifted computer desk  100 ; alternatively, the face plate  160  can also be maintained, such that the electrically-lifted computer desk  100  can be used separately or in combination with the office desk  200 , thus forming a completely novel furniture combination. 
     Referring to  FIG. 7 , an alternative embodiment of a desk is shown. The desk  300  can be the same or similar to desk  100  in all respects except as discussed below. As shown in  FIG. 7 , the desk  300  can have a bottom plate  310  for resting on a surface, such as a conventional, fixed height desktop, or for directly connecting to an office desk, such as office desk  200  ( FIG. 5 ). The desk can have a face plate (not depicted for clarity) which is coupled to a first desktop connecting piece  343  and a second desktop connecting piece  353 . As described with respect to desk  100 , the face plate of desk  300  can be moved with the driving mechanism  320  between a lowered position and a raised position to allow a user to sit or stand in front of the desk  300 . The driving mechanism  320  can include a first fixing piece  321  ( FIG. 8 ), a second fixing piece  322 , a first guide rod  323 , and a second guide rod  324 . 
     The movement of the face plate of desk  300  is provided by the first side-support member  340 , the second side-support member  350 , and an intermediate support member. The intermediate support member can include a sliding rod seat  331 , a first side-support piece  332 , a second side-support piece  333 , and a transverse link  334 . The first side-support piece  332  can include two portions: a first portion  332   a  connected between the transverse link  334  and the sliding rod seat  331 ; and a second portion  332   b  connected between the transverse link  334  and the first guide rod  323 . The second portion  332   b  can include a lower end having a flange  327 . The flange  327  can be secured to a traveling block  325  via a fastening member  329 . The flange  327  can fixedly couple the second portion  332   b  of the first side-support piece  332  to the traveling block  325 . Movement of the traveling block  325  along the first guide rod  323  can also move the second portion  332   b  of the first side-support piece  332  due to the fixed connection. 
     The second side-support piece  333  can include two portions: a first portion  333   a  connected between the transverse link  334  and the sliding rod seat  331 ; and a second portion  333   b  connected between the transverse link  334  and the second guide rod  324 . The second portion  333   b  can include a lower end having a flange  327 . The flange  327  can be secured to a traveling block  325  via a fastening member  329 . The flange  327  can fixedly couple the second portion  333   b  of the second side-support piece  333  to the traveling block  325 . Movement of the traveling block  325  along the second guide rod  324  can also move the second portion  333   b  of the second side-support piece  333  due to the fixed connection. 
     The first side-support member  340  can include a third side-support piece  341  and a fourth side-support piece  342 . The third side-support piece  341  can be coupled at a lower end  341   a  to the bottom plate  310  and at an upper end (not visible) to the first desktop connecting piece  343 . The lower end  341   a  can be pivotally coupled to the bottom plate  310 . The upper end of the third side-support piece  341  can be slidably coupled to the first desktop connecting piece  343 . The upper end of the third side-support piece  341  can be coupled to the first desktop connecting piece  343  in a manner similar to desk  100  as described with respect to  FIG. 2 . That is, the upper end of the third side-support piece  341  can include a guide wheel received in a guide groove located in a flanged edge of the first desktop connecting piece  343 . Accordingly, as the face plate raises and lowers, the upper end can slide with respect to the face plate and the lower end  341   a  can pivot with respect to the bottom plate  310 . 
     The fourth side-support piece  342  can include the second portion  332   b . The fourth side-support piece  342  can be coupled at a lower end  342   a  to the bottom plate  310  and at an upper end  342   b  to the first desktop connecting piece  343 . The lower end  342   a  can be slidably coupled to the bottom plate  310  with a traveling block  325  as previously described. The upper end  342   b  of the fourth side-support piece  342  can be pivotally coupled to the first desktop connect piece  343 . Accordingly, as the face plate raises and lowers, the upper end  342   b  can pivot with respect to the face plate and the lower end  342   a  can slide with respect to the bottom plate  310 . 
     The third side-support piece  341 , the fourth side-support piece  342 , and the transverse link  334  can be coupled to one another at a pivot  347 . As the face plate lowers, the pivot  347  can allow the upper end of the third side-support piece  341  to slide longitudinally away from the upper end  342   b  of the fourth side-support piece  342  and can allow the lower end  342   a  of the fourth side-support piece  342  to slide longitudinally away from the lower end  341   a  of the third side-support piece  341 . This can cause the height of the face plate to decrease as the distance between the respective upper and lower ends of the third side-support piece  341  and fourth side-support piece  342  increases. As the face plate raises, the pivot  347  can allow the upper end of the third side-support piece  341  to slide longitudinally toward the upper end  342   b  of the fourth side-support piece  342  and can allow the lower end  342   a  of the fourth side-support piece  342  to slide longitudinally toward the lower end  341   a  of the third side-support piece  341 . This can cause the height of the face plate to increase as the distance between the respective upper and lower ends of the third side-support piece  341  and fourth side-support piece  342  decreases. 
     The second side-support member  350  can include a fifth side-support piece  351  and a sixth side-support piece  352 . The fifth side-support piece  351  can be coupled at a lower end  351   a  to the bottom plate  310  and at an upper end (not visible) to the second desktop connecting piece  353 . The lower end  351   a  can be pivotally coupled to the bottom plate  310 . The upper end of the fifth side-support piece  351  can be slidably coupled to the second desktop connecting piece  543 . The upper end of the fifth side-support piece  351  can be coupled to the second desktop connecting piece  353  in a manner similar to desk  100  as described with respect to  FIG. 2 . That is, the upper end of the fifth side-support piece  351  can include a guide wheel received in a guide groove located on a flanged edge of the second desktop connecting piece  353 . Accordingly, as the face plate raises and lowers, the upper end can slide with respect to the face plate and the lower end  351   a  can pivot with respect to the bottom plate  310 . 
     The sixth side-support piece  352  can include the second portion  333   b . The sixth side-support piece  352  can be coupled at a lower end  352   a  to the bottom plate  310  and at an upper end  352   b  to the second desktop connecting piece  353 . The lower end  352   a  can be slidably coupled to the bottom plate  310  with a traveling block  325  as previously described. The upper end  352   b  of the sixth side-support piece  352  can be pivotally coupled to the second desktop connecting piece  353 . Accordingly, as the face plate raises and lowers, the upper end  352   b  can pivot with respect to the face plate and the lower end  352   a  can slide with respect to the bottom plate  310 . 
     The fifth side-support piece  351 , the sixth side-support piece  352 , and the transverse link  334  can be coupled to one another at a pivot  347 . As the face plate lowers, the pivot  347  can allow the upper end of the fifth side-support piece  351  to slide longitudinally away from the upper end  352   b  of the sixth side-support piece  352  and can allow the lower end  352   a  of the sixth side-support piece  352  to slide longitudinally away from the lower end  351   a  of the fifth side-support piece  351 . This can cause the height of the face plate to decrease as the distance between the respective upper and lower ends of the fifth side-support piece  351  and sixth side-support piece  352  increases. As the face plate raises, the pivot  347  can allow the upper end of the fifth side-support piece  351  to slide longitudinally toward the upper end  352   b  of the sixth side-support piece  352  and can allow the lower end  352   a  of the sixth side-support piece  352  to slide longitudinally toward the lower end  351   a  of the fifth side-support piece  351 . This can cause the height of the face plate to increase as the distance between the respective upper and lower ends of the fifth side-support piece  351  and sixth side-support piece  352  decreases. 
     The third side-support piece  341 , fourth side-support piece  342 , fifth side-support piece  351 , and sixth side-support piece  352  can move simultaneously such that the face plate remains level during raising and lowering of the face plate. 
     The sliding rod seat  331  can be in threaded engagement with a screw rod (hidden by cover  380 ) such that rotation of the screw rod imparts movement to the sliding rod seat  331 . The cover  380  can substantially cover upper and/or side surfaces of the screw rod. The cover  380  can be metal (such as aluminum), durable plastic, or other materials known in the art. The screw rod and cover  380  can be supported between the driving mechanism  320  and the second fixing piece  322 . The cover  380  can provide a deterrent to user interaction with the screw rod. The sliding rod seat  331  can include a threaded portion that mates with the screw rod. The cover  380  can include one or more openings (e.g., slots) to permit engagement between the threaded portion of the sliding rod seat  331  and the screw rod. Thus, when the screw rod is rotated, the sliding rod seat  331  can be moved along the cover  380  due to the threaded interaction with the screw rod. 
     The sliding rod seat  331  is coupled to the first side-support member  340  and the second side-support member  350  via the transverse link  334 . As described previously, the transverse link  334  moves with the sliding rod seat  331 . As the transverse link  334  moves longitudinally along the screw rod (not visible) due to the sliding rod seat  331 , the pivot point  347  also moves. This longitudinal movement causes the third side-support piece  341 , fourth side-support piece  342 , fifth side-support piece  351 , and sixth side-support piece  352  to pivot with respect to each other. As the transverse link  334  moves toward the driving source  326 , the traveling block  325 , the upper end of the third side-support  341 , and the upper end of the fifth side-support  351  move toward the driving source  326 , thus lowering the height of the face plate. As the transverse link  334  moves away from the driving source  326 , the traveling block  325 , the upper end of the third side-support  341 , and the upper end of the fifth side-support  351  move away from the driving source  326 , thus raising the height of the face plate. 
     The transverse link  334  is coupled to an upper portion of the first portion  332   a  of the first side-support piece  332  and an upper portion of the first portion  333   a  of the second side-support piece  333 . The transverse link  334  is also pivotably coupled at pivot  347  to an upper portion of the second portion  332   b  of the first side-support piece  332  and pivotably coupled at pivot  347  to an upper portion of the second portion  333   b  of the second side-support piece  333 . 
     The lower ends of the second portions  332   b ,  333   b  of the first side-support piece  332 , second side-support piece  333 , respectively, are slidably coupled to the first guide rod  323  and second guide rod  324 , respectively, via traveling blocks  325 . The lower ends of the second portions  332   b ,  333   b  can be fixedly coupled with fasteners  329  to the traveling blocks  325 , as previously described. The traveling blocks  325  can include an aperture allowing the traveling block  325  to slide along the guide rods  323  and  324 . The traveling blocks  325  and guide rods  323 ,  324  can allow for guided travel of the face plate in the direction toward and away from the ends of the desk. The fourth side-support piece  342  and the sixth side-support piece  352  are coupled to the upper portions of the second portions  332   b ,  333   b , respectively, and to the transverse link  334  via pivot  347 . The second portion  332   b  of the first side-support piece  332  and the fourth side-support piece  342  can be integral or can be separate components coupled together. The second portion  333   b  of the second side-support piece  333  and the sixth side-support piece  352  can be integral or can be separate components coupled together. The upper end of the fourth side-support piece  342  can be pivotally coupled to the first desktop connecting piece  343 . The upper end of the sixth side-support piece  352  can be pivotally coupled to the second desktop connecting piece  353 . As described in connection with the desk  100 , the third side-support piece  341  can have an upper end slidably coupled to the first desktop support piece  343  and a lower end pivotally coupled to the bottom plate  310 . For example, the upper ends of the third side-support piece  341  and fifth side-support piece  351  can be slidably coupled via a wheel or wheels engaged in a groove of the first and second desktop connecting pieces  343 ,  353 , respectively. The fifth side-support piece  351  can likewise have an upper end slidably coupled to the second desktop support piece  353  and a lower end pivotally coupled to the bottom plate  310 . 
     The driving mechanism  320  can include a driving source  326 , such as an AC or DC motor that turns the screw rod (not depicted). A portion of the sliding rod seat  331  engages the screw rod and moves laterally therealong in response to the rotation of the screw rod. As the sliding rod seat  331  moves toward the first fixing piece  321 , the transverse link  334  causes the first and second side-support members  340 ,  350  to fold, lowering the face plate of the desk. As the sliding rod seat  331  moves toward the second fixing piece  322 , the transverse link  334  causes the first and second side-support members  340 ,  350  to extend, raising the face plate of the desk. 
     More specifically, when the sliding rod seat  331  moves laterally along the screw rod to and from the driving mechanism  320 , the lower ends of second portions  332   b ,  333   b  of the first side-support piece  332 , second side-support piece  333 , respectively, slide along the first and second guide rods  323 ,  324  respectively. This causes the upper ends of the fourth and sixth side-support pieces  342 ,  352  to pivot with respect to the first and second desktop connecting pieces  343 ,  353 , respectively. At the same time, the upper ends of the third and fifth side-support pieces  341 ,  351  slide with respect to the first and second desktop connecting pieces  343 ,  353 , respectively; and the lower ends of the third and fifth side-support pieces  341 ,  351  pivot with respect to the bottom plate  310 . 
     Referring to  FIG. 8 , the desk  300  is shown rotated such that the driving source  326  is in the front of the desk  300 . As can be seen in this view, the driving source  326  can be a driving source  3261 , such as an AC or DC electric motor. The driving source  3261  can be mounted to a first fixing piece  321 . Thus the screw rod (not visible) and cover  380  are supported between the first fixing piece  321  and the second fixing piece  322 . 
     Referring to  FIG. 9 , an alternative embodiment of a desk is shown. The desk  400  can be the same or similar to either or both of desks  100  and  300  in all respects except the desk  400  can also include a safety-enhancing system. It can be appreciated that omitted reference numerals and discussion of same can be the same or similar to those provided for desk  100  and/or desk  300 . The desk  400  can have a bottom plate  410  and a face plate  460 . The face plate  460  can be movably coupled to the bottom plate  410  in any of the foregoing manners to facilitate raising and lowering of the face plate  460 . 
     With continued reference to  FIG. 9 , the desk  400  can include a safety-enhancing system. Desks  100 ,  300 , and/or  500  can also incorporate a safety-enhancing system. The safety-enhancing system operates in conjunction with the desk&#39;s control system to halt movement of the face plate  460  with respect to the bottom plate  410  (e.g., upward or downward movement) in the event that an object approaches or enters the space between face plate  460  and bottom plate  410 . For example, the control system can include one or more buttons to cause the motor to raise and lower the face plate  460  via the first and second side-support members  440 ,  450 . The safety-enhancing system can interface with the control system to discontinue movement of the face plate  460  in order deter an operator&#39;s finger or hand from being pinched in the first side-support member  440  or the second side-support member  450 . The safety-enhancing system can be a control mechanism and can include a first sensor strip  490  and a second sensor strip  492 . Each of the sensor strips  490 ,  492  can include one or more sensors  490 S,  492 S, respectively. The sensors  490 S,  492 S can be transmitter and/or receiver devices. The one or more sensors  490 S can be selected and located on the sensor strip  490  to align with the one or more sensors  492 S on the sensor strip  492 . In this manner, the sensor strips  490  and  492  provide a light curtain, such as safety curtain  494  between the face plate  460  and the bottom plate  410 . That is, when an object, such as a user&#39;s hand, enters the safety curtain  494 , the one or more sensors  490 S and  492 S will be unable to communicate with one another due to the presence of the object. As a result, the safety-enhancing system can disrupt the power supply to the motor (even if the user continues to press the up or down button), causing the movement of the face plate  460  to stop. The safety-enhancing system can also illuminate a light, such as an indicator light  496 , indicating that an object has passed into the safety curtain  494 . 
     The sensors  490 S and  492 S can be optical sensors, such as infrared grating sensors. The sensors  490 S can transmit an optical signal which is received by the sensors  492 S, or vice versa. When the optical signal is broken, such as by being blocked with an object, the safety-enhancing system signals the motor (not depicted) to halt movement of the face plate  460 , for example, by breaking the circuit that supplies power to the motor. When the object is removed, the optical signal will no longer be blocked and the receiving sensors  492 S will receive the transmitted optical signal. The safety-enhancing system can then restore the power supply to the motor, allowing movement of the face plate  460  to resume. According to embodiments, the safety-enhancing system is active whenever the desk is connected to power and the sensors  490 S,  492 S continually transmit signals between one another. Alternatively, the safety-enhancing system can activate whenever the user pushes the up or down button to cause the face plate  460  to raise or lower. 
     The sensor strips  490 ,  492  are depicted along a top surface of the bottom plate  410  and a lower surface of the face plate  460 , respectively. Alternatively, or additionally, the sensor strips  490 ,  492  can be located along other surfaces of the desk  400 , so long as the sensors  490 S and  492 S can transmit an optical signal to each other. The sensor strips  490 ,  492  are depicted along a side edge of the desk  400 . Alternatively, or additionally, the sensor strips  490 ,  492  can be located along other sides of the desk  400  (e.g. the front edge, rear edge, or opposing side edge). More than one of each sensor strip  490 ,  492  can be provided on more than one surface. For example, sensor strips  490 ,  492  can be located as depicted in  FIG. 9  and also can be located on the bottom plate  410  and face plate  460  along the front edge of the desk  400 . In this manner, an object can be detected entering from the side edge and/or the front edge of the desk  400 . The sensor strips  490 ,  492  can be provided on all edges of the desk  400 . 
     With reference to  FIGS. 10 and 11 , an alternative embodiment of a desk is shown. The desk  500  can be the same or similar to any of desks  100 ,  300 , and/or  400 . Therefore, omitted reference numerals and discussion of the same can be the same or similar to those provided in connection with the aforementioned desks. The desk  500  can have a bottom plate  510  and a face plate (not depicted). The desk  500  can include a driving mechanism  520 . The driving mechanism  520  can be a driving source  526 , such as an AC or DC motor  5261 . The driving mechanism  520  can raise and lower the face plate as previously described. The driving mechanism  520  can include a first fixing piece  521 , a second fixing piece  522 , a first guide rod  523 , and a second guide rod  524 . The movement of the face plate of desk  500  is provided by a first side-support member  540 , a second side-support member  550 , and an intermediate member, as previously described. The intermediate member can include a nut sliding rod seat  531 , a transverse link  534 , and first and second side-support pieces, in the same or similar manner to the previously described desks. The desk  500  can also include a screw rod  525 . The screw rod  525 , first guide rod  523 , and second guide rod  524  can be fixedly mounted between the first fixing piece  521  and the second fixing piece  522 . The nut sliding rod seat  531  can have apertures configured to receive the first guide rod  523  and the second guide rod  524 . The nut sliding rod seat  531  can slide along the first guide rod  523  and second guide rod  524  as the nut sliding rod seat  531  traverses the screw rod  525 . The desk  500  can also include one or more lift-assist springs  528 . Each of the lift-assist springs  528  can be coupled to the bottom plate  510  via connecting member  527 . The lift-assist springs  528  can be located in a groove  527   a  of the connecting member  527 . The lift-assist springs  528  can be secured in the groove  527   a  with a fastening member  527   b . Each lift-assist spring  528  can include a rod head  529  ( FIG. 11 ), such as a gas spring rod head. The rod head  529  can extend through an aperture in the first fixing piece  521 . The lift-assist springs  528  can comprise gas springs, such as a pneumatic spring. However, alternative embodiments can comprise coil springs, elastomers, or other springs known in the art. As shown in  FIG. 11 , each rod head  529  is aligned with the nut sliding rod seat  531 , such that a face of the nut sliding rod seat  531  can engage the rod heads  529 . 
     As the desk  500  is moved to the lowered position, the nut sliding rod seat  531  travels toward the motor  5261 . As the desk  500  approaches the fully lowered position, the nut sliding rod seat  531  compresses the rod heads  529  through the aperture in the first fixing piece  521  and into the body of the lift-assist springs  528 . When the desk  500  is moved to the raised position, the nut sliding rod seat  531  moves away from the rod heads  529 , no longer compressing the rod heads  529 . The energy stored in the compressed rod heads  529  causes the rod heads  529  to extend outward from the aperture in the first fixing piece  521 . The rod heads  529  are propelled forward against the nut sliding rod seat  531 . The force provided by the rod heads  529  against the nut sliding rod seat  531  assists the motor  5261  in moving the nut sliding rod seat  531 , thus assisting in the raising of the desk  500 . 
     During operation of the desk  500 , the lift-assist springs  528  can provide additional lift assistance to the face plate, reducing the load on the motor  5261 . The motor  5261  requires additional current to lift the table surface from a fully lowered position. The addition of the lift-assist springs  528  reduces the initial effort required to lift the table surface; therefore, less initial current is needed for the motor  5261  to lift the table surface from the fully lowered position. This allows for a smaller rate power motor to be chosen or can simply lower the power consumption of the motor  5261 . This can provide an additional benefit, for example, when a heavy load is placed on the face plate. In this instance, the rod heads  529  of the lift-assist spring  528  will push the nut sliding rod seat  531  away from the first fixing piece  521 , raising the first and second side-support members  340 ,  350  while lowering the power required of the motor  5261  during the lifting process. Although two lift-assist springs  528  are depicted, it can be appreciated that more or fewer lift-assist springs can be provided. Additionally, one of ordinary skill in the art will understand, based on this disclosure, that one or more lift-assist springs  528  can be provided in other locations as shown, to provide lift-assistance to the table surface during initial upward movement from the fully-lowered position. 
     The desks  100 ,  300 ,  400 , and/or  500  can comprise one or more materials. For example, the face plate can comprise wood, plastic, metal, composite, laminate, stone, marble, concrete, glass, or other material. The bottom plate can comprise any material capable of supporting the face plate and the support members, such as plastic, metal, composite, etc. The support members, support pieces, links, and sliding members can comprise any material, for example plastic, metal, composite, etc. The pivot connections can comprise a pin or rod extending through a hole, a fastener, or other connection type, with or without a bushing or bearing, capable of pivoting or rotational motion. 
     The embodiments illustrated and discussed in this specification are intended only to teach those skilled in the art the best way known to the inventors to make and use the invention. Nothing in this specification should be considered as limiting the scope of the present invention. All examples presented are representative and non-limiting. The above-described embodiments of the invention can be modified or varied, without departing from the invention, as appreciated by those skilled in the art in light of the above teachings. It is therefore to be understood that, within the scope of the claims and their equivalents, the invention can be practiced otherwise than as specifically described.