Abstract:
The invention relates to a single wheel caster with a support element including a top element and a base element which includes at least one support arm, wherein the base element receives at least one hub for a wheel, wherein a thread protector is arranged on the hub, wherein a fixation device is arranged between the wheel and the support element. It is an object of the invention to provide a novel single wheel caster with substantially reduced assembly complexity. The object is achieved in that the locking device is arranged without additional fastening elements in an interior of the support element between at least one inner surface of the support element and at least on contact surface arranged rotationally fixated at the wheel, wherein the contact surface firmly contacts the locking device when the caster is assembled.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims priority from and incorporates by reference German patent application 10 2014 002 610.8 filed on Feb. 27, 2014. 
       FIELD OF THE INVENTION 
       [0002]    The invention relates to a single wheel caster with a support element essentially including a top element and a base element which includes at least one support arm wherein the base element includes at least one hub for a wheel, wherein a thread protector is arranged on the hub and a fixation device is arranged between the wheel and the support element. 
       BACKGROUND OF THE INVENTION 
       [0003]    A single wheel caster of this general type is known for example from DE 20 2011 005 192 U1 co-owned by applicant. 
         [0004]    Casters of this type and other types are typically completely mounted in a factory and then have to be attached at a later point in time at hospital beds, medical equipment of similar. When mounting a completely delivered caster there are problems over and over again in practical applications where an installation space between wheel and support element for arranging attachment bolts is very small so that it is even difficult and time consuming with specially adapted tooling to attach the complete caster at a rolling frame or similar. This generated the idea to sell casters in a kit. 
       BRIEF SUMMARY OF THE INVENTION 
       [0005]    Thus, it is an object of the present invention to provide a new single wheel caster which significantly reduces assembly complexity. 
         [0006]    The object is achieved by a single wheel caster with a support element, the support element comprising a top element; and a base element which includes at least one support arm, wherein the base element receives at least one hub for a wheel, wherein a thread protector is arranged at the hub, wherein a locking device is arranged between the wheel and the support element, wherein the locking device is arranged without additional fastening elements in an interior of the support element between at least one inner surface of the support element and at least one contact surface arranged rotationally fixated at the wheel, and wherein the at least one contact surface firmly contacts the locking device when the caster is assembled. 
         [0007]    The single wheel caster according to the invention is advantageous in that a locking device can be arranged in the interior of the support element without additional fasteners with low force application so that it is ready to operate. This simplifies assembly of the single wheel caster significantly for a user and improves the options to distribute this caster as a kit. 
         [0008]    In one embodiment of the invention the contact surface associated with the wheel is arranged at the thread protector which provides an additional function to the thread protector in a simple manner. 
         [0009]    An advantageous embodiment of the invention is wherein the locking device is simultaneously made from a wheel locking device and/or a directional locking device. 
         [0010]    In an advantageous embodiment the locking device is formed by a holder, a locking element and a locking lever, wherein the locking element and the locking lever are interlocked at the support without an additional fastener element. This embodiment has the advantage that the locking device can be assembled in a very simple manner from three components that are interlockable with each other. 
         [0011]    Further advantages may be derived from the fact that the locking device can also be attached also without additional fastener elements between the support element and the thread protector solely by mounting the wheel at the support element. 
         [0012]    Eventually a particularly advantageous embodiment of the invention includes support arms which respectively include a support coulisse for the locking device wherein the locking device is partially insertable into an interior of the support element in a portion of the coulisse and wherein the locking device is moveable into a defined end position by a pivot movement along the support coulisse. Through this very simple option to associate the locking device and the support element it is further simplified for a user to mount the locking device in the support element. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    Further advantages of the invention can be derived from a subsequent description of advantageous embodiments of the invention with reference to drawing figures, wherein: 
           [0014]      FIG. 1  illustrates a side view of a support element and a wheel of a single wheel caster in an exploded depiction; 
           [0015]      FIG. 2  illustrates a frontal view of the support element according to the view arrow II in  FIG. 1 ; 
           [0016]      FIG. 3  illustrates a representation according to  FIG. 1  with a support element that is partially arranged at the wheel; 
           [0017]      FIG. 4  illustrates a depiction according to  FIG. 1  with a support element interlocked at the wheel; 
           [0018]      FIG. 5  illustrates a sectional view through the wheel axle/wheel hub; 
           [0019]      FIG. 6  illustrates a view according to  FIG. 3  with an additional cover snap locked on; 
           [0020]      FIG. 7  illustrates an exploded view showing wheel locking device, support element and wheel; 
           [0021]      FIG. 8  illustrates a sectional view of the support element and the locking device at a beginning of assembly; 
           [0022]      FIG. 9  illustrates a view according to  FIG. 6  during assembly of the locking device; and 
           [0023]      FIG. 10  illustrates an exploded view of the locking device. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0024]    In the drawing figures the single wheel caster is designated overall with reference numeral  10 . 
         [0025]    As illustrated in  FIGS. 1 and 2  the single wheel caster  10  includes a wheel  11  with a wheel rim  12  which is provided with an integrally molded running surface  13 . In the portion of the wheel axle  24  (cf.  FIG. 5 ) the wheel  11  is provided with a solid thread protector  15  using an attachment rivet  14 . 
         [0026]    Additionally the single wheel caster  10  is formed by a support element  16  which includes two support arms  17 . 
         [0027]    The thread protector  15  respectively arranged on both sides of the rim  12  is provided with numerous material saving pass through openings D and respectively includes an attachment portion  18 . Additionally the support arms  17  are respectively provided with a so called opposite attachment portion  19 . 
         [0028]    The attachment portion  18  of each thread protector  15  includes offset support ribs  20  which are used for controlled insertion of support bars  22  arranged at an inside  21  of the support arms  17  wherein end portions of the support bars  22  oriented towards the wheel  11  have insertion bevels  23  (cf.  FIG. 8 ). 
         [0029]    Significantly offset above a wheel axle  24  curved undercut portions  25  are arranged on both sides adjacent to the support ribs  20 . Simultaneously a wheel hub element N includes another undercut portion  26  configured as a protruding collar respectively protruding on both sides parallel to an insertion direction x of the opposite attachment portion  19  into the attachment portion  18 . 
         [0030]    Furthermore, the attachment portion  18  is provided on both sides with a support contour  27  which extends respectively from a lower edge of the wheel hub N to the undercut portion  25 . The support contours  27  are specifically configured spring elastic and include a preliminary locking posit on  28  and a finial locking position  29  which will be described infra. 
         [0031]    The opposite attachment portion  19  of the support arms  17  is provided on both sides with curved locking surfaces  30  and additionally provided with a respective interlocking protrusion  31  on both sides at an end portion oriented towards the edge  11 . 
         [0032]      FIGS. 1-5  individually illustrate the assembly of the single wheel caster  10  and the attachment of the support element  16  and the wheel  11  at one another. 
         [0033]      FIG. 1  shows that the support element  16  is oriented for attachment purposes so that the support arms  17  are oriented towards the wheel hub N with their opposite attachment portions  19 . 
         [0034]    Comparing  FIGS. 1 and 3  shows that moving the support element  16  towards the wheel  11  the support bars arranged at the inner surfaces  21  are initially inserted on both sides into an intermediary cavity  32  between the support ribs  20  using the insertion bevels  23 . This already provides an exact positioning of the opposite attachment portion  19  relative to the attachment portion  18 . Further movement in insertion direction x (cf.  FIG. 3 ) causes the interlocking surfaces  30  of the opposite attachment portion  19  to partially reach under the curved undercut portion  25  of the attachment portion  18 , wherein the interlocking protrusions  31  are in the preliminary locking position  28  of the support contours  27 . 
         [0035]    Further movement of the support element  16  towards the wheel  11  yields the configuration according to  FIG. 4  in which the interlocking protrusions  31  are already interlocked in the final interlocking position  29  and the interlocking surfaces  30  are arranged with large surfaces below the curved undercut portions  25 . 
         [0036]    Additionally as evident from  FIG. 5  the undercut portions  26  arranged on both sides of the wheel hub N are respectively undercut in an interlocking manner by the bar shaped protrusion V of the opposite attachment portion  19 . 
         [0037]    Due to the multiple form locking connection of each support arm  17  with the associated thread protector  15  in the portion of the two undercut portions  25  and of the two undercut portions  26  and due to the fact that the four undercut portions  25 ,  26  are respectively substantially offset from each other this yields a very stable load bearing connection between the support element  16  and the wheel  11 . 
         [0038]    From  FIG. 6  it is additionally apparent that an additional cover  33  can be attached at the thread protector after mounting the support element  16  and the wheel  11 . Interlocking receivers are respectively fabricated into the support arms  17  in a non-illustrated manner wherein interlocking devices that are not illustrated and are arranged at an inside of the cover  33  can engage the interlocking receivers. 
         [0039]    This additional arrangement of a cover  33  facilitates to configure the thread protector  15  as a structural component with plural pass through openings which greatly simplifies production of this component and reduces product costs wherein the function of the thread protector is still preformed in its entirety due to the combination with the cover  33 . 
         [0040]      FIGS. 7-10  further illustrate that the single wheel caster  10  described supra can be provided with a locking device  34 . As apparent from  FIG. 10  the locking device  34  is formed by a locking element  35  which includes a device for activating the directional locking device  36  and two devices for activating the wheel locking device  37 . 
         [0041]    Additionally the locking element  35  is provided with two interlocking protrusions  38  which are used for attaching a support  39 . The support  39  includes two interlocking openings  40  where the recited attachment protrusions  38  interlock when attaching the support  39  at the locking element  35 . 
         [0042]    Additionally the support  39  includes interlocking protrusions  41  which are used for attaching a locking lever  42 . The locking lever  42  is in turn provided with interlocking recesses  43  illustrate din dashed lines which facilitates a pivotable attachment of the locking lever  42  at the support  39  in a simple manner. 
         [0043]    The locking device  34  which is interlocked without additional fasteners and which is illustrated in  FIG. 7  together with the support element  16  and the wheel  11  in an exploded view can now be positioned at the support element  16  without additional fasteners as well and in a simple manner. This process is illustrated in  FIGS. 8 and 9 . 
         [0044]    It is evident from  FIG. 8  that the locking device  34  is diagonally inserted into an interior of the support element  16  until both lower edges of the locking lever  42  respectively designated as  44  in  FIG. 10  contact on both sides at an arcuate contour  45  of the support element  16  (c.f.  FIG. 1 ). Thereafter an arcuate pivot movement y moves the locking device  34  with the lower edges  44  of the locking lever  42  along the arcuate contours  45  of the support element  16  until the locking device  34  is arranged in a predetermined end position in the support element  16 . 
         [0045]    In this context it is important, however, that the thread protector elements  15  additionally include two contact surfaces  46 , wherein one respective contact surfaces as a function of a direction in which the locking device  34  is mounted at the wheel  11  interacts with the opposite contact surfaces  47  arranged at the locking device  34 . This means in particular that the contact surfaces  46  of the thread protector  15  and the contact surfaces  47  of the locking device  34  contact each other with their entire surfaces after completing the insertion movement for attaching the support element  16  at the wheel  11 , wherein the locking device  34  is fixated between an inner surface I of the support element and the contact surfaces  46  and  47 . When actuating the locking lever  42 , however, within certain limits a pivot movement of the locking element  35  including the device for actuating the directional locking device  36  and the device for actuating the wheel locking device  37  is feasible, wherein the support  39  is held in place. This pivot movement, however, is necessary so that on the one hand side the non illustrated directional locking device can be actuated in the support element  16  and on the other hand side the partially illustrated wheel brake can also be actuated. 
         [0046]    Eventually as already recited supra the unit including the support element  16  and the locking device  34  can be disengageably interlocked in the same manner with the wheel  11 . 
         [0047]    In particular  FIG. 7  illustrates a spring elastic lobe  48  that is cut clear on three sides and arranged in a center of the insertion portion of the thread protector  15 , wherein the lobe is provided with a roof shaped actuation contour  49 . On its back side the spring elastic lobe  48  includes a non-illustrated teeth portion which is arranged opposite to an annular teething  50  of the rim  12 . 
         [0048]    The locking device  34  is provided with a device for actuating the wheel locking device  37 . The device  37  includes an actuation portion that is formed at a respective inner surface which is not illustrated wherein the actuation portion is arranged opposite to the roof shaped contour  49  in assembled condition. When actuating the locking lever  42  the locking element  35  is pivoted by a particular angular amount wherein the actuation protrusion acts against the roof shaped actuation contour  49  and presses the spring elastic lobe  48  with the non-illustrated teething portion arranged behind the spring elastic lobe  48  into the teething of the wheel hub  12 . This provides a reliable wheel blocking. 
         [0049]    Additionally the described pivoting of the locking device  34  causes the directional locking device  36  to pivot as well and to engage into the non-illustrated directional locking device after pivoting so that a directional fixation is provided as well. 
       REFERENCE NUMERALS AND DESIGNATIONS 
       [0000]    
       
         
           
               10  single wheel caster 
               11  wheel 
               12  wheel rim 
               13  running surface 
               14  attachment rivet 
               15  thread protector 
               16  support element 
               17  support arm 
               18  attachment portion 
               19  opposite attachment portion 
               20  support ribs 
               21  inner surface support arm 
               22  support bars 
               23  insertion bevel 
               24  wheel axle 
               25  undercut portions (curved) 
               26  undercut portions (collar) 
               27  support contour (on both sides) 
               28  preliminary interlocking position 
               29  final interlocking position 
               30  locking surfaces of  19   
               31  interlocking protrusions 
               32  intermediary space 
               33  cover 
               34  locking device 
               35  locking element 
               36  actuation device for directional locking device 
               37  actuation device for wheel locking device 
               38  attachment protrusions 
               39  support 
               40  interlocking openings 
               41  interlocking protrusions 
               42  locking lever 
               43  interlocking recesses 
               44  lower edge of locking lever  42   
               45  arcuate contour of  16   
               46  contact surfaces of  15   
               47  contact surfaces of  34   
               48  spring elastic lobe 
               49  roof shaped actuation contour 
               50  teething at wheel rim 
             x insertion direction 
             y arcuate pivot movement 
             N wheel hub 
             V bar shaped protrusion 
             I inner surface of  16   
             D pass through openings