Abstract:
An improved stop block assembled to NAAMS™ specifications for providing a locating device for a movable member. The stop block has at least one crowned end for positioning to face the movable member and to accurately stop the movable member when the movable member comes in contact with the stop block. The improved stop block includes a proximity switch installed within the stop block for sensing when the movable member contacts the stop block. The improved stop block may also include an actuating device communicating with the proximity switch for sending a signal to a controlling device.

Description:
FIELD OF THE INVENTION 
     The invention relates to an improvement over a stop block assembled to industry-wide specifications for providing a locating device for a movable member. 
     BACKGROUND OF THE INVENTION 
     In an assembly having a reciprocal member such as a piston on a rod it may sometimes be required to know when both the piston reaches the end of its cycle at a terminating point, as well as knowing that the piston stops exactly and repetitively at a precise position against the terminating point. As is conventionally known, a cylinder is provided having a movable member located on a rod and having terminating points at each end of the rod. The terminating points are defined by stop blocks. 
     To provide precise locations for stopping the movable member, crowned stop blocks are provided in the barrier end so that the movable member stops exactly at the center point of the crowned stop block. The crowned stop blocks are precision manufactured parts manufactured to the specification and tolerances of the North American Automotive Metric Standards. Hence, these precision crowned stop blocks are known in the industry as NAAMS™ stop blocks. Although the NAAMS™ stop block provides a precise location stop of the movable member, in many applications, a proximity sensor/switch is also required to sense the position of the moving object. 
     Since the use of a proximity switch and a NAAMS™ stop block are used in many applications, it is desirable to incorporate the proximity switch within the NAAMS™ stop block such that it provides a single component having dual functions. Providing a NAAMS™ stop block with a proximity switch incorporated therein would eliminate the need to adjust the position of the proximity switch each time there is an adjustment for the NAAMS™ stop block. 
     SUMMARY OF THE INVENTION 
     The invention is an improved stop block especially for a stop block manufactured to industry standards which provides a locating device for a movable member wherein the stop block has at least one crowned end for positively positioning and facing the movable member and to accurately stop the movable member in the center of a crowned end when the movable member comes in contact with the stop block. The improvement includes a proximity switch installed within the stop block for sensing when the movable member contacts the stop block. The improved stop block of the present invention is interchangeable within other existing stop block applications manufactured and assembled to industry-wide specifications. 
    
    
     Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
     FIG. 1 is a perspective view of a typical application of a stop block manufactured to the industry standards where the assembly includes a proximity switch separate from the stop block; 
     FIG. 2 is a stop block manufactured to an industry standard having a proximity switch incorporated therein according to the present invention; 
     FIG. 3 is a top planar view of the stop block in FIG. 2, with certain details shown in hidden lines; 
     FIG. 4 is a perspective view of one side of a stop block manufactured according to industry standards therein according to a third embodiment for use in vertical applications, wherein the stop block is in contact with a movable member; 
     FIG. 5 shows a perspective view of the opposing side of the stop block and movable member in FIG. 4 with certain details shown in hidden lines; 
     FIG. 6 is a elevational view of the stop block and movable member of FIGS. 4 and 5 in a separated condition with certain details shown in hidden lines; 
     FIG. 7 is a elevational view of the stop block and movable member of FIGS. 4 and 5 in a contact condition with certain details shown in hidden lines; and 
     FIG. 8 is a elevational view of the movable member in FIG. 6 approaching the stop block from an angular direction with certain details shown in hidden lines. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Looking at FIG. 1, there is shown a typical application of a stop block  10  manufactured to certain industry standards, and particularly to standards set by the North American Automotive Metric Standards, hereinafter referred to as NAAMS™. The application may include a cylinder  12  having at least one rod  14  and a plate  16  attached to said rod such that the plate  16  reciprocally moves with the reciprocal movement of the rod. (The plate  16  may be replaced with a piston or other movable member attached to the rod  14 .) The movement of the rod  14  and plate  16  are bounded by terminating points  18 , and particularly are bounded by terminating points  18  having NAAMS™ stop blocks  10  incorporated therein. The NAAMS™ stop block  10  is positioned to the terminating points or end barriers  18  such that the crowned end surface  20  of the stop block  10  faces the plate  16 . The crowned end surface  20  of the NAAMS™ stop block  10  has a precise center point which contacts the plate such that the plate  16  stops at the precise and measurable location each time the plate  16  contacts the stop block  10 . 
     In the prior art, a particular application of a reciprocally moving plate  16  or cylinder  12  would require a sensing device to determine when the plate  16  had arrived at one end of its stroke or the other, as well as precisely stopping the plate  16  at the predetermined locations. Although the NAAMS™ stop block  10  would precisely stop the plate  16  at a predetermined location, it does not provide a sensing means for the operator to know when the plate  16  had reached the end of its stroke or when the plate  16  had been stopped by the NAAMS™ stop block  10 . As a result, the prior art required a proximity switch  24  positioned adjacent to each end of the stroke of the plate  16  at a stationary point along the side of the rods  14 . Flags  26  were then positioned along the side ends of the plate  16  so that as the plate  16  moved toward one end of its stroke, the proximity switch  24  adjacent to that end would sense the flag  26  when the plate  16  contacts the stop block  10  and thereby sends the appropriate signal. The present invention desires to eliminate the separate proximity switches  24  that are located along the side ends of the reciprocal cylinder and the brackets  28  upon which the proximity switches  24  are mounted. Further, the present invention desires to eliminate the need of separate flags  26  in most instances. 
     FIGS. 2-5 show a NAAMS™ stop block  10  with a proximity switch  30  installed therein. In FIGS. 2 and 3, the proximity switch  30  is positioned in the crowned end surface  20  at the precise center section of the stop block  10  so that the proximity switch  30  is exposed. A conventional NAAMS™ stop block  10  includes a pair of through apertures  34  (shown in hidden lines) extending from the crowned end surface  20  to the opposite wall  22  for bolting the NAAMS™ stop block  10  to an end wall of a cylinder or slide assembly. A center through aperture  52  extends from the crowned end surface  20  to the opposite wall  22  for feeding the proximity switch  30  into the NAAMS™ stop block. In other embodiments, the through aperture  52  may extend through an adjacent wall  21  of the crown end surface  20 . A top notch  40  may be cut into the back or opposite wall  22  for fitting the electric conduit  50  of the proximity switch  30  therethrough for communication to an appropriate controller device (not shown). 
     The installation and position of the proximity switch within the NAAMS™ stop block  10  as shown in FIGS. 2-3 wherein the proximity sensor  30  is exposed in the crowned end surface  20  of the stop block  10  is preferred for applications where the plate or other movable member  16  is moving towards the NAAMS™ stop block  10  in a horizontal direction. 
     In conditions and applications where the plate or movable member  16  is moving in a vertical direction, it is not advised to place a proximity switch  30  in a vertical position such that the proximity switch  30  is facing upwardly. A proximity switch  30  placed in an upward position can inadvertently be damaged or provide false readings by objects, both metallic and non-metallic, falling onto the proximity switch  30  by way of gravity. FIGS. 4-7 show various views of an alternative embodiment for use in applications where the plate or other movable member  16  is moving in a vertical direction. FIGS. 4,  5 , and  7  show a movable member  16  in contact with the NAAMS™ stop block  10 . FIGS. 6 and 7 show sectional views of the movable member  16  and NAAMS™ stop block  10 , wherein FIG. 6 shows the movable member  16  approaching, but spaced, from the NAAMS™ stop block  10 , while FIG. 7 shows the movable member  16  in contact with the NAAMS™ stop block  10 . Looking at FIG. 6, the NAAMS™ stop block  10  is shown to provide a aperture  52  for the proximity switch  30  such that it is on a vertical wall of the NAAMS™ stop block  10  so that it is not facing vertically upward on the crowned end surface  20 . The vertical wall in this embodiment can be any of the four adjacent walls  21  to the crowned end surface  20 . The movable member  16  is then provided with a flag  60  releasably secured with a bolt  64  to the movable member  16  such that a portion of the flag  60  extends beyond the peripheral edges of the movable member  16 . The flag  60  is positioned so that it will contact or cover the proximity switch  30  precisely when the forward wall  62  of the movable member  16  contacts the NAAMS™ stop block  10 . FIGS. 4 and 7 show the movable member  16  in contact with the NAAMS™ stop block  10 , and covering the proximity switch  30 . The proximity switch  30  is not shown in FIG. 4; and the proximity switch is shown in hidden lines in FIG.  7 . 
     Further, as can be seen in FIGS. 4,  6 ,  7 , and  8  the NAAMS™ stop block  10  can also be adapted to sense a movable member  16  coming into contact with the stop block  10  from an angular direction. A cavity  69  having an angular portion  70  is provided for receiving the flag  60  as the movable member  16  approaches and then contacts the NAAMS™ stop block  10 . The cavity  69  allows the movable member  16  and its associated flag  60  to approach the NAAMS™ stop block  10  such that the flag  60  is sensed by the proximity sensor  40  when the movable member  16  contacts the NAAMS™ stop block  10 . FIG. 8 shows the movable member  16  approaching the NAAMS™ stop block from an angular direction according to this embodiment. The angularity of the portion cavity  70  can be changed according to the application of the system and the relative movement of the movable member  16  in relationship with the NAAMS™ stop block  10 . 
     The improved embodiments of the NAAMS™ stop block  10  provides a universal device that does not require adjustment when the reciprocal member of an assembly is realigned or changed. The improved stop block  10  having a proximity switch  30  further eliminates brackets for positioning proximity switches  30  along the sides of the cylinder assembly. 
     While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.