Patent Publication Number: US-7584932-B2

Title: Construction prop

Description:
FIELD OF THE INVENTION 
   The present invention is related to a construction equipment, and more particularly to a prop. 
   BACKGROUND OF THE INVENTION 
     FIGS. 1 and 2  show a conventional prop  10  for supporting moldboards. The prop  10  includes an outer tube  12 , a threaded tube  13  fixed at a top end of the outer tube  12  and an inner tube  15  telescopically fitted in the threaded tube  13  and the outer tube  12 . The threaded tube  13  is formed with a pair of axial slots  14 . The inner tube  15  is formed with several pairs of pinholes  16  arranged at equal intervals. A locating nut  17  is adjustably screwed on the threaded tube  13 . An insertion pin  18  is passed through the slots  14  of the threaded tube  13  and inserted into one pair of pinholes of the inner tube  15 . In use, the inner and outer tubes  15 ,  12  are adjusted to a necessary length and then the insertion pin  18  is inserted through the slots  14  of the threaded tube  13  into one pair pinholes  16  of the inner tube  15 . The insertion pin  18  is supported by the locating nut  17 . By means of turning the nut  17 , the length of the inner tube  15  extending out of the outer tube  12  can be adjusted, whereby the prop serves to support a moldboard. 
   The conventional prop  10  has some shortcomings as follows: 
   First, the length of the prop is adjusted by means of turning the locating nut  17 . It takes much time to complete such procedure. Therefore, a user can hardly quickly conveniently adjust the length of the prop to a necessary length. 
   Second, such prop  10  is designed for bearing pressure only. Therefore, the prop  10  cannot bear pulling force. In the case that an axial pressure is applied to the prop  10 , the inner tube  15  is supported by the nut  17  without being retracted into the outer tube  12 . However, in the case that an axial pulling force is applied to the prop, the inner tube will slide and displace. Accordingly, the prop can only bear one-way action force, that is, the axial pressure. Therefore, such prop is inapplicable to the situation of bidirectional action force so that the application range of such prop is narrowed. 
   U.S. Pat. No. 6,467,741 entitled “steel prop capable of bearing bidirectional applied force” of this applicant discloses a prop capable of bearing bidirectional action force. However, it is relatively inconvenient to operate such prop. In addition, the prop has a relatively complicated structure. 
   SUMMARY OF THE INVENTION 
   It is therefore a primary object of the present invention to provide a prop which can be quickly adjusted in length. 
   It is a further object of the present invention to provide the above prop which is able to bear both axial pressure and tension. Therefore, the application range of the prop is widened. 
   The present invention can be best understood through the following description and accompanying drawings wherein: 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a conventional prop; 
       FIG. 2  is an enlarged view of a part of the prop of  FIG. 1 ; 
       FIG. 3  is a perspective view of a first embodiment of the prop of the present invention; 
       FIG. 4  is a perspective exploded view of the first embodiment of the prop of the present invention according to  FIG. 3 ; 
       FIG. 5  is a side view according to  FIG. 3 ; 
       FIG. 6  shows that the prop of the present invention is used to support a moldboard; 
       FIG. 7  is a view according to  FIG. 6 , showing that the inner tube of the prop is lowered; 
       FIG. 8  shows that the prop of the present invention is restored to the state of  FIG. 6 ; 
       FIG. 9  is a front view of the first embodiment of the prop of the present invention, which is used in another mode; 
       FIG. 10  is a side view according to  FIG. 9 ; and 
       FIG. 11  is a perspective view of a second embodiment of the prop of the present invention, showing the use thereof. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Please refer to  FIGS. 3 and 4 . According to a first embodiment, the prop  20  of the present invention includes an outer tube  30 , an inner tube  40 , a locating nut  50 , an insertion pin  70  and a controlling member  60 . 
   A top end of the outer tube  30  is a threaded section  32  with a thread formed on outer circumference of the threaded section. The threaded section and the outer tube  30  can be a one-piece member or two pieces fixedly connected with each other. A pair of slots  34  is axially formed on the threaded section  32  of the outer tube  30 . 
   The inner tube  40  is telescopically fitted in the outer tube  30 . The inner tube  40  is formed with several pairs of pinholes  42  axially arranged at equal intervals. 
   The locating nut  50  is screwed on the threaded section  32  of the outer tube  30 . By means of turning the nut  50 , the height of the nut  50  on the threaded section  32  can be adjusted. An annular rib  52  is formed on outer circumference of the nut  50 . Preferably, the annular rib  52  is positioned on top edge of the nut  50 . Two lugs  54  are disposed on two sides of the nut  50 . 
   The controlling member  60  is a collar member. A pair of through holes  62  is radially formed on the circumference of the controlling member  60 . An insertion section  64  is formed on bottom face of the controlling member  60 . In this embodiment, the insertion section  64  is composed of two hook edges (a) formed on two sides of the controlling member. Two recessed/projecting structures are formed on top face of the controlling member  60  at equal intervals. Preferably, each of the recessed/projecting structures is a 180-degree arc. Each of the recessed/projecting structures has a standard position  65 , a releasing position  66  formed on one side of the standard position  65  and an adjoining face  67  located between the standard position  65  and the releasing position  66 . The adjoining face is a slope, two ends of which respectively adjoin with the standard position and the releasing position. An inclined guide face  68  is formed on the other side of the standard position  65 . The guide face  68  has a higher end  681  and a lower end  682 . The higher end  681  adjoins with the standard position  65 . In this embodiment, the higher end  681  of the guide face  68  is higher than the standard position  65 . However, this is not limited. The higher end can be alternatively at the same height as the standard position. The other side of the releasing position  66  adjoins with the lower end  682  of the guide face  68  of the other recessed/projecting structure. 
   When assembled, the insertion section  64 , that is, the hook edges (a) of the controlling member  60  are hooked with the annular rib  52  of the locating nut  50 , whereby the controlling member  60  is connected with the locating nut  50  as shown in  FIGS. 3 and 6 . The controlling member  60  is directly overlaid on the nut  50 . Then the locating nut  50  is screwed on the threaded section  32  of the outer tube  30 . With the nut  50 , the controlling member  60  is fitted on the threaded section  32  of the outer tube. Then the inner tube  40  is telescoped into the outer tube  30  as shown in  FIG. 3 . Finally, the insertion pin  70  is inserted through the prop  20 . A resiliently retractable steel ball  72  is embedded in front end of the insertion pin  70 . 
   The connection between the controlling member  60  and the nut  50  is characterized in that when the nut  50  is adjusted to another height, the controlling member  60  changes its height along with the nut. Furthermore, the controlling member is movably/rotatably connected with the nut. Therefore, the controlling member and the nut are rotatable relative to each other. That is, when turning the nut  50 , the controlling member  60  is not rotated along with the nut  50 , and vice versa. 
   The prop of the present invention can be used in two manners. The first manner is to bear the axial pressure. Referring to  FIG. 6 , with the prop  20  positioned upright, the support board  36  of the bottom end of the outer tube  30  contacts the ground. The top end of the inner tube  40  is moved to a position near the moldboard (not shown). Then the insertion pin  70  is fitted through the slots  34  of the outer tube  30  and inserted into one pair of the pinholes  42  of the inner tube  40 . And make the insertion pin rest on the standard position  65  of the controlling member  60 . Then the locating nut  50  is turned to rise. At this time, the controlling member  60 , the insertion pin  70  and the inner tube  40  are moved upward along with the nut. An L-shaped rod  75  as shown in  FIG. 3  or other suitable rod can be inserted into the hole  541  of the lug  54  of the nut to turn the nut. During the turning operation, the controlling member  60 , the insertion pin  70  and the inner tube  40  are simply moved without rotating. After the support board  44  of the top end of the inner tube  40  abuts against the moldboard, the prop  20  serves to support the moldboard to bear the pressure in grouting. 
   After the concrete is hardened, the prop can be quickly separated from the moldboard. The controlling member  60  is turned leftward from the position of  FIG. 6  to the position of  FIG. 7 . At this time, the insertion pin  70  leaves the standard position  65  to drop onto the releasing position  66  which is lower. Simultaneously, the inner tube  40  quickly drops to a certain height along with the insertion pin  70 . At this time, the top end of the inner tube quickly separates from the moldboard. Accordingly, it is unnecessary for a user to turn the nut  50  for lowering the inner tube. Instead, by means of turning the controlling member, the prop can be quickly separated from the moldboard to save time for lowering the inner tube. When the insertion pin  70  leaves the standard position  65  to drop onto the releasing position  66 , the insertion pin will first contact the adjoining face  67  and then reach the releasing position  66 . The adjoining face  67  provides a buffering effect so as to prevent the insertion pin from directly gravitationally dropping from the standard position onto the releasing position. 
   When the controlling member  60  is turned leftward from the state of  FIG. 7 , the insertion pin  70  goes from the releasing position  66  to the guide face  68  and moves along the guide face from the lower end  682  of the guide face to the higher end  681  thereof as shown in  FIG. 8 . At this time, the insertion pin  70  is restored to the state of  FIG. 6  and the insertion pin  70  and the inner tube  40  are relocated on the standard position  65  for next use. 
   In the second manner, the prop  20  is able to bear bidirectional action force. Referring to  FIGS. 9 and 10 , the insertion pin  70  is fitted through the through holes  62  of the controlling member  60 , the slots  34  of the outer tube  30  and one pair of pinholes  42  of the inner tube  40 . According to this arrangement, due to the nut  50 , the controlling member  60  is located on the outer tube  30  and cannot displace along the axis of the prop. Relatively, the insertion pin  70  and the inner tube  40  are restricted by the controlling member  60  from displacing. Under such circumstance, no matter whether the inner tube is stressed or tensioned, the inner tube will not slide. Similarly, by means of turning the nut  50 , the length of the prop can be adjusted. 
   Accordingly, the prop can bear axial pressure and tension and thus is applicable to those fields other than supporting a horizontal moldboard. For example, the prop is usable for building a scaffold, a stage, etc. In addition, the prop serves as a link or an oblique lever for construction site. Therefore, the prop of the present invention is versatile and multifunctional. 
     FIG. 11  shows a second embodiment of the prop  80  of the present invention. The inner and outer tubes  84 ,  82 , the locating nut  86 , the controlling member  88  and the insertion pin  89  of this embodiment are identical to those of the first embodiment and thus will not be repeatedly described hereinafter. 
   Two support boards  90 ,  92  are respectively pivotally connected with free ends of the inner and outer tubes  82 ,  84 . Therefore, the support boards  90 ,  92  can freely swing. The prop  80  is arranged in the state of  FIG. 9 . Accordingly, the prop can be inclined as an oblique support rod for fixing an upright moldboard  95 . 
   The prop of the present invention can be quickly lowered, whereby the prop can be quickly separated from the moldboard to save operation time and speed detachment of the moldboard. Moreover, the prop of the present invention is able to bear bidirectional action force so that the usage of the prop is widened. 
   The above embodiments are only used to illustrate the present invention, not intended to limit the scope thereof. Many modifications of the above embodiments can be made without departing from the spirit of the present invention.