Abstract:
Supports for geomatic equipment, and in particular geomatic poles, can come in the form of bipods and tripods. The support system can be selectively configured as a bipod support and as a tripod support. No modification needs to be made to the geomatic pole, the system is independently capable of configuration. The position of legs of the supports is particularly selected to provide stability in both the bipod and tripod configurations.

Description:
BACKGROUND OF THE INVENTION 
   This invention relates generally to devices which support and hold equipment and more particularly to a foot for such devices suitable for holding geomatic equipment and accessories. 
   Although the art of surveying is old, recent improvements in equipment, such as automatic electronic total surveying stations, have increased the accuracy of the surveying instruments far beyond what was possible previously. Where accepted accuracy for equipment in the not too distant past was 20 seconds of a degree, accuracy is now commonly required to be 1 second of a degree. At these levels of precision, the instruments and many of their accessories must be supported in a manner which is consistent and stable. Accordingly, there is a need for closer examination of support structure used for surveying equipment so that improvements in instrumentation will not be lessened by inadequate supports. Further, the cost of surveying equipment makes it highly undesirable to damage it by failure of the supports because of instability. 
   Pole supports used in the surveying field typically take the form of bipods or tripods, but conceivably any number of legs could be provided. Conventionally, it has been necessary to provide completely separate inventories of bipods and tripods to meet the needs of different customers and for different applications. Legs of these supports are usually freely pivotable about a head of the support to swing toward each other for ease of carrying the support when not in use. A support having three or more legs can support equipment or other items above and out of contact with the ground. Typically, bipods are used to support surveying equipment such as a surveying pole, which also contacts the ground, but tripods may also be used to support surveying poles. The stability of such supports can be compromised in situations where there are forces (e.g., wind and loads from the surveying equipment) acting on the support and tending to tip the support over. In that case, one of the legs is subjected to an upward force component tending to raise the leg up as the support pivots about a point(s) of contact of the other leg(s) with the ground. 
   Presently, there is little or no resistance provided by the legs to such upward forces other than the weight of the leg. Even if there are stakes associated with the legs that penetrate the ground, the upward force tends to be directed right along the long axis of the stakes so that they are lifted out of the ground. The problem is compounded by the fact that the legs conventionally are mounted for pivoting freely about a horizontal axis. Even if the support does not tip over, if one leg loses contact with the ground or the frictional resistance to pivoting movement of the leg becomes sufficiently small, the leg will swing in toward the center of the support. The support is unlikely to regain stability when this happens. Should the support move back toward its original position, the leg having pivoted inwardly is no longer in position to engage the ground in a stable position. The center of gravity of the combined support and surveying equipment may lie outward of the point where the leg re-contacts the ground so that the entire unit topples over in the opposite direction from the initial tipping movement. Alternatively as the leg pivots inwardly, the weight of the leg exerts a smaller torque resisting the tipping motion so that the motion may continue causing the unit to collapse. If instability of the support causes it to move, even where it does not fall over, accuracy is compromised. 
   Although the present invention has particular application for use in supporting surveying and geographic positioning equipment, it is not limited to such applications. As used herein “geomatic” is intended to encompass surveying and geographic positioning. The invention is envisioned as being useful to support equipment and other items having no relation to surveying or geographic positioning. 
   SUMMARY OF THE INVENTION 
   Generally, a support system for supporting a geomatic pole comprises first, second and third legs each having mounting structure for connection to the geomatic pole. The first and second legs are capable of connection to the geomatic pole independently of the third leg for two point support of the geomatic pole, and the third leg is capable of connection to the geomatic pole with the first and second legs for three point support of the geomatic pole. 
   In another aspect of the present invention, a support system for supporting a geomatic pole comprises a head including a first head element and a second head element, and first and second legs mounted on the first head element. The first head element is formed for releasable connection to the geomatic pole for two point support of the geomatic pole. A third leg is mounted on the second head element. The second head element is formed for releasable connection separate from the connection of the first head element for use in conjunction with said first and second legs and first head element for three point support of the geomatic pole. 
   The objects and features of the present invention will be in part apparent and in part pointed out hereinafter. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective of a bipod support holding a surveying pole in an upright position on a plot of ground; 
       FIG. 2  is a side elevation of the bipod support and surveying pole; 
       FIG. 2A  is an enlarged, fragmentary elevation of the bipod support, showing a foot of the bipod support embedded in the ground; 
       FIG. 3  is an enlarged fragmentary elevation of a lower end of a leg of the bipod showing a foot thereof; 
       FIG. 4  is a section taken in the plane including line  4 - 4  of  FIG. 3 ; 
       FIG. 5  is a perspective of the foot as viewed from a vantage interior of the bipod support; 
       FIG. 6  is a perspective of the foot as viewed from a vantage exterior of the bipod support; 
       FIG. 7  is an interior perspective of another form of the foot; 
       FIG. 8  is a longitudinal section of the foot and leg portion of  FIG. 9 ; 
       FIG. 9  is a fragmentary exterior perspective of the foot and a portion of the leg with a leg weight exploded therefrom; 
       FIG. 10  is the perspective of  FIG. 9  but showing the weight as connected to the foot; 
       FIG. 11  is an exterior perspective of a foot having a stake attached thereto; 
       FIG. 12  is a fragmentary perspective of a bipod support leg including the foot of  FIG. 11 ; 
       FIG. 13  is an enlarged, fragmentary perspective of the bipod support and surveying pole of  FIG. 1  showing a connection of the bipod support to the surveying pole; 
       FIG. 14  is a fragmentary perspective of the bipod support showing a head of the support partially exploded; 
       FIG. 15  is an enlarged perspective of a front wall of the head showing an inner surface thereof; 
       FIG. 16  is an enlarged perspective of the front wall of the head showing an outer surface thereof; 
       FIG. 17  is an enlarged perspective of a rotary actuator of the head; 
       FIG. 17A  is a fragmentary side elevation of the rotary actuator with a portion broken away to show a ramp at the bottom of a slot on the underside of the rotary actuator; 
       FIG. 18  is an elevation of the head with the rotary actuators removed and showing a fragmentary portion of one leg as received in the head for hinged connection therein; 
       FIG. 19  is an elevation of the bipod support and a surveying pole in a collapsed position and illustrating a line of sight to a bottom point of the surveying pole; 
       FIG. 20  is an enlarged, fragmentary perspective of the support and pole of  FIG. 19 ; 
       FIG. 21  is a further enlarged perspective of a leg retainer of the surveying pole; 
       FIG. 22  is a fragmentary perspective of an upper end of the bipod support from a vantage above the support; 
       FIG. 23  is a fragmentary perspective of an upper end of the bipod support from a vantage below the support; 
       FIG. 24  is a top plan view of the bipod support and a surveying pole; 
       FIG. 25  is a perspective of a tripod support, a surveying pole and accessories; 
       FIG. 26  is an enlarged fragmentary perspective of an upper end of the tripod support, surveying pole and accessories; 
       FIG. 27  is a top plan view of the tripod support and the surveying pole with accessories removed; 
       FIG. 28  is an enlarged fragmentary perspective of a joint of a support leg; 
       FIG. 29  is the perspective of  FIG. 28  with a first leg section of the leg exploded from a second leg section; 
       FIG. 30  is a section taken in the plane including line  30 - 30  of  FIG. 28 ; 
       FIG. 31  is an exploded perspective of an extension locking device of the leg; 
       FIG. 31A  is an enlarged, fragmentary vertical section of lock members and a wedge of the locking device illustrating the construction of resilient members of the locking device; 
       FIG. 32  is a section like  FIG. 30  but with parts removed to show additional details of construction; 
       FIGS. 32A and 32B  are enlarged, fragmentary sections of the locking devices illustrating both locked and unlocked positions; 
       FIG. 33  is a schematic section of the locking device in a lock position; 
       FIG. 34  is a schematic section of the locking device in an unlock position; 
       FIG. 35  is a fragmentary perspective of a surveying pole having a modular mounting system of the present invention; 
       FIG. 36  is a perspective of a modular mount of a first embodiment; 
       FIG. 37  is a perspective of a modular mount, partially exploded, of a second embodiment; 
       FIG. 38  is a perspective of a modular mount of a third embodiment; 
       FIG. 38A  is an exploded perspective of the modular mount of  FIG. 38 ; 
       FIG. 38B  is an exploded perspective of a modular mount of a fourth embodiment; 
       FIG. 38C  is an exploded perspective of a modular mount of a fifth embodiment; 
       FIG. 39  is a longitudinal section of the modular mount of  FIG. 38  with compression nuts thereof exploded from a tubular mount body; 
       FIG. 40  is a perspective of a tripod support and surveying pole with accessories mounted thereon; 
       FIG. 41  is an enlarged, fragmentary perspective of a surveying pole having a modular mount thereon illustrating attachment of four items at one level; 
       FIG. 42  is a perspective of a modified mount for adjustable support of an article from generally as seen from the rear of the article; 
       FIG. 43  is an exploded perspective of the modified mount and article of  FIG. 42 ; 
       FIG. 44  is an exploded perspective like  FIG. 43 , but from a front vantage; 
       FIG. 45  is a perspective of a mount having a clipped on adjustable support; 
       FIG. 46  is an elevation of the mount of  FIG. 45 ; 
       FIG. 47  is a perspective of two components of a connection system of the present invention; 
       FIG. 48  is a perspective of the components of  FIG. 47  in an engaged position from a vantage generally opposite to that of  FIG. 47 ; 
       FIG. 49  is a side elevation of the connected components of  FIG. 48 ; 
       FIG. 50  is a perspective of a first modified version of one connector component of the system; 
       FIG. 51  is a perspective of a second modified version of a second modified version of the one connector component of the system; 
       FIG. 52  is a perspective of a mount having an adjustable support of a second embodiment supporting an article; 
       FIG. 53  is a perspective of the mount and article of  FIG. 52 , partially exploded; 
       FIG. 54  is a perspective of the mount of  FIG. 52  wherein the adjustable support is clipped onto a mount body; 
       FIG. 55  is a fragmentary perspective of a leg including a modified foot assembly; 
       FIG. 56  the perspective of  FIG. 55  with parts exploded; 
       FIG. 57  is a section taken in the plane including line  57 - 57  of  FIG. 58 , a screw of the foot assembly not being sectioned and being shown in a retracted position; 
       FIG. 58  is an inside elevation of the leg and foot assembly; 
       FIG. 59  is a section taken in the plane including line  59 - 59  of  FIG. 60 , the screw  357  being in a fully extended position; 
       FIG. 60  is an inside elevation of the leg and foot assembly; 
       FIG. 61  is a an outside elevation of the foot on soil; 
       FIG. 62  is a outside elevation of the foot on concrete; 
       FIG. 63  is a bottom plan view of the foot. 
   

   Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. 
   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring now to the drawings, and in particular to  FIGS. 1 and 2 , a support of the present invention is shown in the form of a bipod support  1  holding a surveying pole  3  in an upright position on a plot of ground G (the numbers designated their subjects generally). The pole  3  is extensible and retractable and includes an upper section  5  and a lower section  7  telescopingly receiving the upper section. The upper and lower pole sections  5 ,  7  are held in a selected position of extension by a clamp  9  located at the joint of the upper and lower pole sections. Typically, the upper section  5  has indicia (not shown) indicating the height above the ground. A pointed tip  11  is mounted on the lower end of the lower pole section  7  and engages the ground G. A level  13  mounted on the lower pole section  7  is used to position the surveying pole  3  vertically upright. In the illustrated embodiment, a prism  15  at the top of the pole  3  is used to sight or determine positions with laser, modulated infrared, angular and/or GPS position locators or the like. The prism  15  reflects light back to the position locator for establishing the location of the prism in a survey. However, it is to be understood that other items could be located at the top of the pole without departing from the scope of the present invention. Reference is made to co-assigned U.S. application Ser. No. 09/648,172, filed Aug. 25, 2000 (the disclosure of which is incorporated herein by reference), showing and describing a surveying pole of the same general type as the present invention. 
   The bipod support  1  includes a head  17  connected to the surveying pole  3 , a first leg  19  and a second leg  21  (the reference numbers designating their subjects generally). The first and second legs  19 ,  21  are mounted on the head  17  for pivoting inwardly and outwardly with respect to the head about a generally horizontal pivot axis. Each leg ( 19  and  21 ) includes a first section  23  telescopingly received in a second section  25  so that the leg can be selectively increased or decreased in length. The operation of the leg ( 19  or  21 ) to extend and retract will be described in more detail hereinafter. Each leg ( 19  and  21 ) further includes a foot (generally indicated at  27 ) at its free end (opposite the head  17 ) which engages the ground G. The foot  27  is capable of penetrating the ground G to facilitate positive location of the ends of the first and second legs. A ground penetrating portion (generally indicated at  29 ) of each foot  27  penetrates the ground G and is obscured from view by the ground in  FIG. 1 . In  FIG. 2 , the ground penetrating portion  29  of the foot  27  of leg  19  may be seen under the ground. 
   A description of the foot  27  will be made with reference to the leg  19 , the foot on the other leg  21  being of the same construction and arrangement. Referring now to  FIGS. 2A ,  3 ,  5  and  6 , each foot  27  is shown to include a sleeve  31  receiving an end portion of the leg  19 . The ground penetrating portion  29  extends from one side of the sleeve  31  in an inward direction (generally toward the head  17  and surveying pole  3 ) and a pedal  33  extends from the opposite side. A mount generally indicated at  35  and located at the top of the sleeve may be used to attach an article (not shown) to the foot  27 . The mount  35  is undercut on both sides, leaving laterally projecting lips  37  for use in a tongue in groove type connection which is the same as will be described more fully below. The word “undercut” is used to herein to describe the final shape of the mount  35 , not the method for forming the mount, which in a preferred embodiment would be molded with the other parts of the foot  27 . Holes  39  extending through the mount  35  in the undercut portion can be used for bolting an article to the foot  27 . In the illustrated embodiment, the ground penetrating portion  29 , sleeve  31 , pedal  33  and mount  35  are formed as one piece from a suitable polymeric material. However, it is to be understood that the foot  27  may be formed in multiple pieces and from other materials (e.g., metal) without departing from the scope of the present invention. 
   The ground penetrating portion  29  has a tip  41  which, as can be seen in  FIG. 2A , is located inward and under the leg  19  when penetrating the ground G. In the illustrated embodiment, the entire ground penetrating portion  29  occupies this position with earth located above the ground penetrating portion and between the portion and the leg  19 . Therefore, support  1  resists forces in both directions along the length of the leg  19  to maintain stability of the support. Forces applied downwardly along the leg  19  are resisted by the rigidity of the leg and engagement of the foot  27  with the ground G. Upwardly directed forces along the leg  19  are resisted by the ground penetrating portion  29 . Upwardly directed forces might occur if the bipod support  1  and surveying pole  3  were subject to a force tending to tip them to the right as shown in  FIG. 2 . The weight of the earth above the first wall  43  of the ground penetrating portion  29  holds the foot  27  in place against such upward movement. The ground penetrating portion  29  is particularly constructed to facilitate retention, and also initial penetration of the ground G. More particularly, the ground penetrating portion  29  comprises a first wall  43  and a second wall  45  intersecting the first wall generally at right angles so that the ground penetrating portion has a generally “T” shape in cross section (see  FIG. 4 ). The first wall  43  tapers from its widest dimension near the sleeve to the tip  41 , roughly in the shape of a spade. The angle made by the first wall  43  relative to the centerline C of the leg  19  (and sleeve  31 ) preferably about 90° (i.e., perpendicular) to about 150°. As illustrated in  FIG. 3 , the angle of the first wall  43  is about 120°. 
   The second wall  45  acts as a gusset to strengthen the ground penetrating portion  29  without substantially increasing the cross section of the ground penetrating portion presented to the ground G when the foot  27  is pushed into the ground. The second wall  45  has a roughly triangular shape, tapering toward the tip  41 . Thus, it may be seen that the ground penetrating portion  29  is shaped to facilitate penetration of the ground. Retention of the ground penetrating portion  29  is facilitated by barbs  47  formed in the first and second walls which extend in a transverse direction across the first wall  43 , and continue along the second wall  45  on both sides thereof. The barbs  47  have the cross sectional shape of an arrow pointed toward the tip  41  of the ground penetrating portion  29 . As the ground penetrating portion is pushed into the ground G, the leading edges of the barbs  47  facilitate pushing the earth aside to allow the ground penetrating portion  29  to pass into the ground. However as each barb  47  passes through the earth and in its final position of penetration, earth moves behind a wide end  48  of the barb and tends to block movement of the ground penetrating portion  29  out of the ground G in the opposite direction. A similar effect occurs when the shoulders  49  of the first wall  43  immediately adjacent the foot  27  pass into the ground. Earth can cover the projecting ends  49  further to resist extraction of the ground penetrating portion  29 . 
   Referring to  FIGS. 3 ,  5  and  6 , it may be seen that the pedal  33  includes a foot pad  51  projecting outwardly from the sleeve  31  to an outer wall  53  extending at an angle to the foot pad and generally in plane with the first wall  43  of the ground penetrating portion  29 . A bridge wall  55  extends between the sleeve  31 , foot pad  51  and outer wall  53  and connects the three to form a rigid structure having a low weight and employing minimal material. A hole  57  in the bridge wall  55  can be used to connect items (not shown) to the foot  27 . The foot pad  51  includes a foot engagement surface having grooves  59  to enhance traction on the surface. The angle the foot pad  51  makes with the center line C of the sleeve  31  (and hence the leg  19 ) is selected to that at least a substantial component of a force applied by pressing down on the foot pad  51  is directed along the first wall  43  of the ground penetrating portion  29  toward the tip  41 . In a preferred embodiment, the foot pad  51  makes an angle with the center line C of the sleeve  31  which is greater than or equal to about 100°. 
   Modified versions of the foot  27  shown in  FIG. 7 ,  FIGS. 8-11  and  FIG. 12  are designated generally at  27 A,  27 B and  27 C, respectively. Corresponding parts of the modified feet  27 A,  27 B,  27 C are indicated by the same reference numbers used for parts of the foot  27 , but with a following alphabetic identifier. Like the version of the foot  27  shown in  FIGS. 1-6  the modified versions of the foot  27 A,  27 B,  27 C each includes a sleeve ( 31 A,  31 B) which receives a lower end portion of the leg  19 . As shown in  FIG. 8 , a lower end  61  of the leg  19  is received almost to the bottom of the sleeve  31 B and at least a portion of the ground penetrating portion  29 B is directly radially opposite the leg. The foot  27 B extends in an axial direction beyond the lower end  61  of the leg  19  only a very short distance. Thus, the fully retracted length of the leg  19  including the foot  27 B having the projecting ground penetrating portion  29 B is not substantially greater than it would be without the foot. It will be understood that as the angle of the first wall  43 B of the ground penetrating portion  27 B moves more toward 90° to the center line of the sleeve  31 B, the axial extent of the foot  27 B beyond the lower end  61  of the leg  19  is further reduced. 
   Referring to  FIG. 7 , the ground penetrating portion  29 A of the foot is modified by lengthening the barbs  47 A on the first and second walls  43 A,  45 A so that they contact each other without intervening flat spaces present on the ground penetrating portion  29  of  FIGS. 1-6 . The mount  35 A includes two identical undercut formations  63 A on opposite, outer and inner sides of the sleeve  31 A, both of which are capable of sliding, tongue in groove connection to an article (not shown). As shown in  FIGS. 9 and 10 , the presence of two mounting formations  63 B allows one or more articles to be attached to the foot  27 B by bolting on opposite sides of the foot. In the illustrated embodiment, the article is shown as a leg weight having first and second members (designated  65  and  67 , respectively) capable of being attached on laterally opposite sides of the foot  27 B. The second weight member  67  has four smooth holes generally in the four corners of the member which receive bolts  69  through the second weight member. The bolts  69  pass through the top and bottom holes  39 B formed in the undercut portion of the mounting formations  63 B and into threaded holes  70  in the second weight member  65 . As the bolts  69  are tightened down, the first and second weight members  65 ,  67  are clamped against the mounting formations  63 B ( FIG. 10 ). The weight members  65 ,  67  are formed so that they receive a portion of the foot and have ridges  71  which are received in the undercut portions of the mounting formations  63 B. 
   The version of the foot  27 B shown in  FIG. 9  has a foot pad  51 B with an undulating (rather than grooved) foot engagement surface. Moreover, the pedal  33 B is particularly formed to facilitate a tongue in groove connection of an article (not shown). The outer wall  53 B of the pedal  33 B is wider than the foot pad  51 B defining a ridge  73 B which is opposed by a ridge  75 B formed in the bridge wall  55 B of the foot. The ridges  73 B,  75 B define a groove used to mount articles on the foot  27 B. The same arrangement of ridges  73 B,  75 B is present on the side of the foot  27 B not seen in  FIG. 9 . The bridge wall  55 B is thicker than the bridge walls  55 ,  55 A of the  FIGS. 5 and 7  embodiments, and does not entirely close off the opening between the sleeve  31 B, foot pad  51 B and outer wall  53 B. Three holes  77 B are formed in the bridge wall  55 B and extend completely through the bridge wall. 
   One example of an article which can be mounted on the foot is a stake  79  illustrated in  FIG. 11 . The stake  79  has a long body  81  with a pointed end projecting substantially beyond the tip  41 B of the ground penetrating portion  29 B of the foot  27 B when ground conditions demand deeper penetration to secure the leg  19 . Although the stake body  81  is shown with a conventional form, it is contemplated that the stake could be barbed and/or have a small cross section (like the T-shaped cross section of the ground penetrating portion) without departing from the scope of the present invention. A head  83  of the stake  79  is formed with a channel  85  having at its free edges opposed, inwardly projecting lips  87  which are slidingly received in the grooves defined by opposed ridges  73 B,  75 B of the foot  27 B to connect the stake to the foot. The lips  87  have a generally “L” shape in cross section and present a flat surface to the bottom of the groove. The flat surfaces each have three holes which are in registration with the three holes  77 B in the bridge wall. The number of holes may be other than three without departing form the scope of the present invention. Further connection is achieved by passing bolts  89  through the holes in the lips  87  and bridge wall  55 B. The bolts  89  can be secured by nuts (not shown) or by internally threading the holes in one of the lips  87 , or in another suitable manner. 
   A modified form of the foot  27 B shown in  FIG. 9  is shown in  FIG. 12  and indicated generally by reference character  27 C. The foot  27 C has a closely similar construction to the foot  27 B. However, there is no mount corresponding to mount  35 B of  FIG. 9 . The foot  27 C will not be further described herein. Parts of the foot  27 C corresponding to those of foot  27 B will be indicated by the same reference number, but with the suffix “C”. 
   A retainer  91  located at the joint of the first and second leg sections  23 ,  25  releasably retains the lower end of the first leg section  23  in the second leg section  25 . Although not shown, a retainer could be formed with structure for mounting accessories onto the leg  19 . Referring to  FIGS. 29 and 30  illustrating the leg sections  23 ,  25  at the joint, the leg sections are formed to be snapped together and apart as needed for cleaning, repair or replacement. For example, a second leg section (not shown) having a different foot or mounting structure could be attached to the support  1  in place of the second leg section  25 . The lower part of the first leg section  23  has apertures  105  through which respective ears  107  project, extending out to the sides of the first leg section. The ears  107  are made of a resiliently deformable material. Deformation or flexing is enhanced by weakening regions around the ears  107 . As shown in  FIG. 31 , slots  109  are formed around the ears  107  to facilitate inward flexing of the ears. In the illustrated embodiment, the ears  107  are formed as part of a locking device described below, and also function to attach the device to the first leg section  23 . It is not necessary for the ears  107  to be formed as a part of another leg structure to fall within the scope of the present invention. For instance, the ears  107  could be formed as a single piece separate from the locking device. 
   When the first leg section  23  is telescopingly received in the second leg section  25  (as shown in  FIG. 30 ), the ears  107  engage the inner surface of the second leg section, helping to center the first and second leg sections and helping to eliminate relative lateral movement (“slop”) between the leg sections. The ears  107  are engageable with a rim  111  of the retainer  91  attached at the joint to prevent inadvertent withdrawal of the first leg section  23  from the second leg section  25 . The rim  111  of the retainer  91  extends inwardly from an inner wall of the second leg section  25  forming an opening  113  which is about the same size (or only slightly larger) than the outer dimensions of the first leg section  23 . Thus, because the ears  107  project outwardly from the first leg section  23 , they cannot fit through the opening  113  without deforming. Alternatively, the ears  107  could be relatively rigid and the rim  111  could be deformable, or both the ears and the rim could be deformable to permit the ears to move past the rim out of the opening.  FIG. 30  shows the first leg section  23  fully extended from the second leg section  25  with the ears  107  engaging the underside of the rim  111  preventing further extension of the first leg section. In normal operation of the bipod support leg  19  the first and second leg sections  23 ,  25  will be prevented from separating by the ears  107 . Because the ears are deformable, application of sufficient force to the first and second leg sections  23 ,  25  in an axial direction will cause the ears  107  to resiliently deform inwardly into the second leg section  25  and allow the first leg section  23  to snap past the rim  111  and out of the second leg section  25 . Reconnection of the leg sections  23 ,  25  can be made by applying a force to the leg sections in opposite directions so that the ears  107  deform and snap past the rim  111  in the other direction. The ears  107  return to their undeformed condition inside the second leg section  25  to again inhibit inadvertent separation. 
   The first and second leg sections  23 ,  25  are also preferably held against rotation relative to each other about the center line C of the leg  19 . The first and second leg sections  23 ,  25  have corresponding cross sectional shapes which are not round so that relative rotation is not permitted when the leg sections are engaged with each other. Accordingly, the foot  27 B is held in position with the ground penetrating portion  29 B projecting inwardly. In this way, the foot  27 B is prepared to be pushed into the ground G without having to manually position the foot about the axis of the leg  19 . However, it is envisioned that leg sections of round cross section (not shown) could be used. In that event, the foot pad of the pedal is preferably formed substantially wider and with traction features (not shown) arranged to enhance traction both lengthwise and widthwise of the foot pad so that it is possible using one&#39;s foot to position the ground penetrating portion about the center line of the leg before pushing it into the ground G. 
   Another feature of the present invention can work in conjunction with the foot ( 27 ,  27 A,  27 B,  27 C) of the present invention to increase stability of the bipod support  1 . More particularly, and with reference to  FIGS. 13-18 , each leg  19 ,  21  can be locked by hinge locks (generally indicated at  115 ) against pivoting angularly with respect to the head  17  to prevent the leg from swinging inward if the leg momentarily loses gripping engagement with the ground G. Thus, the weight of the leg ( 19  or  21 ) is always maximally applied to resist tipping of the bipod support  1  and surveying pole  3  in a direction which would cause the leg to lift off the ground. It will be understood that this feature, while useful independently, acts beneficially in conjunction with the gripping action of the ground penetrating portion ( 29 ,  29 A,  29 B,  29 C) of the foot ( 27 ,  27 A,  27 B,  27 C) to resist such tipping motion. 
   The head  17  has one of the hinge locks  115  for each leg to lock the leg in a fixed angular position relative to the head. Referring generally to  FIGS. 13 and 14 , the head  17  comprises a top wall  117 , a bottom wall  119 , a back (or “first”) wall  121  and a front (or “second”) wall  123  which are connected together to form a box structure. The back wall  121  is formed by three generally planar members, including outer members  125  arranged at angles to a center member  127  for setting the angle of separation of the legs  19 ,  21 . A roughly triangular brace  129  connected to the center member  127  strengthens the head  17  and provides a location for securing the top and bottom walls  117 ,  119  to the back wall  121 . The outer members  125  each have tangs  131  two of which project upward from an upper edge of the member and two of which project downward from a lower edge of the member (all four of the tangs  131  of only one of the outer members may be seen in  FIG. 14 ). The front wall  123  has two outer members  133  and a thin center member  135 . The outer members  133  of the front wall  123  also have tangs  137  projecting upwardly from their upper edges and projecting downward from their lower edges. The top wall  117  and bottom wall  119  each have angled outer members  139  and a pie-shaped center member  141 . The interior faces of the top and bottom walls  117 ,  119  are formed with channels  143  along their inner edges and channels  145  along their outer edges which receive and retain the tangs  131  of the back wall  121  and tangs  137  of the front wall  123 , respectively. The top wall  117 , bottom wall  119 , back wall  121  and front wall  123  are secured together by three screws  147  which are received through holes  149  in the top wall into threaded holes in the top of the brace  129 , and by three screws  151  received through holes  153  in the bottom wall into threaded holes (not shown) in the bottom of the brace. As connected together, the walls  117 ,  119 ,  121  and  123  form a box giving the head  17  strength. 
   A large diameter hinge pin  155  projects forward from each of the outer members  125  of the back wall  121 . The hinge pin  155  provides a relatively large cylindrical surface on which the leg  19  may pivot. For example the diameter of the hinge pin  155  may be 1½ inches and the length of the hinge pin may be 1 7/16 inches. A cap  157  mounted on an upper end of the head  17  of each leg  19 ,  21  is joined to a tubular sleeve  159  sized to slide onto the hinge pin  155  in close fitting relation. The tubular sleeves  159  (and hence the legs  19 ,  21 ) are capable of free pivoting motion on their respective hinge pins  155 . The sleeves  159  are retained on the hinge pins  155  by the back wall  121  and the front wall  123  of the head  17 . 
   Referring particularly to  FIG. 14 , the hinge lock  115  includes first detents associated with the head  17  and second detents associated with the leg ( 19  or  21 ). Only one of the hinge locks  115  of the bipod support  1  will be described, the other being identical. The first detents comprise a set of detents  163  formed on the interior surface of the outer member  133  of the front wall  123  and extending around an opening  165  in the front wall ( FIG. 15 ). The second detents include a set of detents  167  on each of the axially facing ends of the sleeve  159 . The detents in each of the sets  163 ,  167  are in the form of ridges  169  (see  FIG. 15 ) extending generally radially of the pivot axis of the leg  19 . The ridges  169  are spaced apart a distance slightly more than the width of each ridge so that a ridge of one set of detents  163 ,  167  may fit between adjacent ridges of another set. Collectively, the ridges  169  give each of the detent sets a serrated appearance. The set  167  of second detents on one side of the sleeve  159  opposes the back wall  121  of the head  17 , and the set  167  of second detents on the opposite end of the sleeve opposes the set  163  of first detents on the front wall  123 . The opposing sets of detents ( 167  and  163 ) can be brought into engagement so that the detents mesh with each other, preventing rotation of the sleeve  159  relative to the back and front walls  121 ,  123  of the head  17  and locking the leg  19  in place. 
   Meshing and releasing of the detents  169  is permitted because the front wall  123  is capable of moving to change the distance between the opposing outer members  125 ,  133  of the back and front walls  121 ,  123 .  FIG. 18  illustrates the head  17  and a sectioned portion of the sleeve  159  received on the hinge pin  155 . The width of the back wall tang  131  received in the channels  143  of the top and bottom walls  117 ,  119  is substantially identical to the width of the channels so that the back wall  121  is held against movement toward or away from the front wall  123 . However, the tangs  137  of the front wall  123  and the front wall itself are thinner than the width of the channels  145  in the top and bottom walls  117 ,  119  receiving those tangs. As a result, the front wall  123  may move toward and away from the back wall  121 . Movement of the outer member  133  of the front wall  123  away from the outer member  125  of the back wall  121  causes the opposing sets of detents ( 167  and  163 ) to release from each other, permitting the leg  19  to pivot freely on the hinge pin  155 . This is the position illustrated in  FIG. 18 . Movement of the outer member  133  of the front wall  123  toward the outer member  125  of the back wall  121  meshes the opposing detent sets, locking the leg  19  in a selected angular position. 
   To selectively mesh and release the opposing sets of detents, a handle  171  (broadly, “actuator”) is provided which is mounted on an end of the hinge pin  155  by a screw  173  and washer  175  for rotation about the pivot axis of the leg  19 . As shown in  FIG. 17 , the handle  171  further includes a tubular spindle  174  having axially extending channels  174 A on its exterior surface. The spindle  174  is received through the front wall opening  165  into an axial passage  177  of the hinge pin  155  and into a bearing  176  (see  FIG. 18 ) rotatably mounted inside the axial opening  177 . The bearing  176  has axially extending bungs  178  which are received in the channels  174 A of the spindle  174  and have a releasable, interference fit with the spindle so that the bearing turns with the spindle. The screw  173  passes through the front wall opening  165 , out of the spindle  174 , through the bearing  178  into a threaded hole (not shown) at a closed end of the axial passage  177  opposite the open end. A finger grip  179  extending outwardly from a round central portion  181  of the handle  171  facilitates gripping the handle to turn it ( FIG. 17 ). 
   Referring to  FIG. 16 , the front wall  123  is formed with tabs  183 . Three tabs are spaced around each of the openings  165  in the front wall  123  and project forward from the front wall. The tabs  183  are received in respective arcuate slots  185  on the underside of the handle  171  (see  FIG. 17 ). The bottom of the slots  185  are formed as arcuate ramps  187 , as may be seen in  FIG. 17A . Thus, the slots  185  are shallower at one end and deeper at the opposite end. As mounted on the hinge pin  155 , the tabs  183  engage and ride on the arcuate ramps  187  in the slots  185  of the handle  171 . One of the tabs  183  as received in the slot into engagement with the ramp  187  is illustrated in phantom in  FIG. 17A . In the position of the handle  171  shown in  FIGS. 13 and 14 , the tabs  183  are in the deepest part of the slots  185 . In this position, the front wall  123  is allowed to move away from the back wall  121  releasing the opposing detents ( 167  and  163 ) from their meshing engagement. Thus, the locking device is unlocked and the leg  19  may be pivoted freely. Turning the finger grip  179  of the handle  171  downward, causes the tabs  183  to slide up the arcuate ramp  187  to a shallow portion of the slot. The handle  171  is fixed by the screw  173  from movement along the pivot axis of the leg  19  toward or away from the back wall  121 , so the outer member  133  of the front wall  123  is pushed toward the outer member  125  of the back wall, enmeshing the opposing sets of detents ( 167  and  163 ). Thus, it may be seen that the legs  19 ,  21  are locked and unlocked with a small turn of the handle  171 . Other constructions for producing movement of the front wall  123  may be employed without departing from the scope of the present invention. For instance, a handle and front wall may be formed with interengaging ramps (not shown). 
   Use of the bipod support  1  as attached to the surveying pole  3  is further facilitated by a leg retainer  191  mounted on the lower pole section  7  of the surveying pole, as illustrated in  FIGS. 19-21 . The leg retainer  191  comprises a ring  193  which is capable of being attached to the surveying pole  3  such as by gluing, or in a less permanent fashion. A shelf  195  projecting outwardly from the ring  193  is enclosed by the ring and a retaining wall  197  extending around the peripheral edge of the shelf and projecting upwardly therefrom. The leg retainer  191  is mounted on the pole  3  so that the shelf  195  extends outwardly from the pole on the opposite side of the pole from the head  17  of the bipod support  1 . In a stowed position of the bipod legs  19 ,  21 , the legs are retracted and the tips  41  of the ground penetrating portions  29  are received on the shelf  195  within the retaining wall  197  so that the feet  27  are held in place by the leg retainer  191 . To place the tip  41  of the ground penetrating portion  29  of one leg (e.g., leg  19 ), the leg is first retracted to a length where the tip is higher than the retaining wall  197  of the leg retainer  191 . The leg  19  is pivoted so that the tip  41  is over the shelf  195 , and the leg is extended to bring the tip into engagement with the shelf within the retaining wall  197 . The other leg  21  is stowed in the same way. The head  17  is preferably made of a resilient polymeric material. The position of the legs  19 ,  21  as stowed departs somewhat from the pivot path of the legs allowed by the hinge pin  155 . Accordingly, the head  17  and/or legs  19 ,  21  are slightly resiliently deflected in the stowed position. In another version of the bipod support (not shown), the leg retainer  191  is omitted and the legs  19 ,  21  are retained in a stowed position (substantially as shown in  FIG. 19 ) by locking the hinge locks  115  of each leg. 
   The bipod support  1  is constructed for quick attachment and release from the surveying pole  3 . Referring to  FIG. 13 , the surveying pole  3  is equipped with a mount, generally indicated at  201 , affixed to the pole at the upper end of the lower pole section  7 . The mount  201  includes two identical undercut formations  203  on opposite, outer and inner sides of the mount. The formations  203  are both capable of sliding, tongue in groove connection to an item, such as the bipod support  1 . The mount  201  will be more fully described hereinafter. Reference is made to  FIG. 35 , showing the mount  201  on a surveying pole  3  on a larger scale. 
   The head  17  of the bipod support  1  has a channel  205  defined by opposite, vertically extending walls  207  having lips  209  projecting toward each other over the channel (see  FIGS. 22 and 23 ). The upper end of the channel  205  is open, but an end wall  211  constituting an extension of the bottom wall  119  of the head  17  closes the lower end of the channel. The bipod support  1  is attached to the surveying pole  3  by aligning the grooves on the mounting formation  203  with the lips  209  on the channel walls  207  of the head  17  and sliding the mounting formation down into the channel  205  until the mounting formation engages the end wall  211  closing the lower end of the channel. The mounting formation  203  is restrained from moving out of the channel  205  by a gate knob  213  rotatable about a vertical axis to frictionally engage the upper mounting formation to hold it in place relative to the head  17 , and to move away from the channel to permit the mounting formation to be removed from or inserted into the channel. The gate knob  213  is mounted for rotation by a bolt  215  received in a circular base  217  on the top wall  117  of the head  17  ( FIG. 14 ). The bolt  215  is threaded into a nut  218  on the underside of the top wall  117  so that the gate knob  213  may rotate relative to the head  17 . Other devices to hold the head  17  on the surveying pole  3  (not shown) are contemplated. For instance, a lever to actuate the gate knob could be located remotely from the knob, or the knob could also hook the mounting formation in the fashion of a window lock. 
   In one preferred embodiment, the bipod support  1  is part of a support system which can be converted from two legged support of the surveying pole  3  (or other supported item) to a three legged or tripod support. For that reason, the legs  19  and  21  are best arranged so that they are spread apart farther than a conventional bipod. However, a conventional spacing of the legs  19  and  21  could be used without departing for the scope of the present invention. As shown in  FIG. 24 , the legs  19 ,  21  are separated by an angle of about 105°, but could be arranged at an angle greater than 90° and less than 120° for use in the support system. This positioning facilitates support of the surveying pole  3  both when the bipod support  1  is used by itself and when used with a single leg support (generally indicated at  221 ) collectively to form a tripod support, as shown in  FIG. 27 . The angle between a leg  223  of the single leg support  221  and each of the legs  19 ,  21  of the bipod support is approximately 127.5°, providing opposition of the legs  19 ,  21  and  223  to support the surveying pole  3 . 
   In the context of the support system, the head  17  of the bipod support  1  constitutes a “head element”. The single leg support  221  includes a head element  225  having a similar construction to the head element  17  of the bipod support  1 , but sized as needed for a single leg  223 . The head elements  17 ,  225  of the bipod support  1  and the single leg support  221  collectively constitute a “head” of the support system. The single leg support  221  is attached to the mount in a manner substantially identical to the bipod support  1 . However, it is to be understood that a single leg support could be attached to a bipod support which is in turn attached to the pole  3  (not shown). In that event, the leg support would still be considered capable of independent, or separate attachment to the pole  3 , even though the attachment is indirect through the bipod support. Moreover, the pivoting connection of the leg  223  to the head element  225  is the same except for sizing, and will not be further described. It is noted that the leg  223  can be releasable locked both in a selected angular position relative to the head element  225  and in a position of telescoping extension just as described above for leg  19  of the bipod support  1 . Although the bipod support  1  and the single leg support  221  are shown, other arrangements are possible. For example, all of the supports in the system could be single leg supports  221 , or two bipod supports  1  could be used at the same time. The number of supports and legs can be other than two or three without departing from the scope of the present invention. Moreover, the supports  1 ,  221  could be used to hold an item (not shown) which does not itself contact the ground. 
   A locking device (generally designated at  228 ) for locking the first and second leg sections  23 ,  25  in a fixed position of extension (or retraction) is illustrated in  FIGS. 28-34 . The description of the locking device  228  will be made with reference to one of the legs  19 , the locking devices in the other legs ( 21 ,  223 ) being identical. The locking device  228  is configured for easy operation by depressing a button  229  located at the upper end of the first leg section  23  to release the locking device, as will be explained more fully. An upper surface  231  of the button  229  is slanted so that even though the leg  19  extends at an angle to vertical, the upper surface faces substantially upward for ease of access to press down (see. e.g.,  FIG. 13 ). This ergonomic construction helps the button  229  to be accessible no matter on what side of the support a user is standing. 
   As shown in  FIGS. 33 and 34 , the button  229  is connected by a screw  232  to a tubular rod  233 , which is internally threaded at the top to receive the screw. The screw  232  is fixed (such as by gluing) to the rod  233  so that the two are fixed rotationally. The button  229  is secured between the head of the screw  232  and an upper end of the rod  233  so that the button, screw and rod move conjointly in translation, but the screw and rod are allowed to rotate relative to the button The rod  233  extends down through the hollow interior of the first leg section  23 , between lock members  235  to a wedge  237  connected to the bottom end of the rod below the lower end of the head  17 . The rod  233  and wedge  237  move with the button  229  conjointly up and down along the axis of the leg  19 . The lower end of the rod  233  is externally threaded and attached by threads to the wedge  237 . Rotation of the screw  232  rotates the rod  233  and, depending upon the direction of rotation, draws the wedge  237  nearer to the button  229  or moves it farther away. Two spaced apart bushings  239  ( FIG. 29 ) are located in and supported by the first leg section  23 . The bushings  239  receive the rod  233  through them to guide the rod and support it against buckling. 
   As may be seen in  FIG. 31 , the lock members  235  are opposed to each other and each have tabs  241  which fit in slots  243  of the opposing lock member to loosely connect the lock members together. The lock members  235  together define two close fitting guide openings  244  in an upper guide portion of the lock members. The guide openings  244  receive the rod  233  between the lock members  235  to center the rod and wedge  237  in the second leg section  25 . The lock members  235  each include the ears  107 , described above, which permit the first and second leg sections  23 ,  25  to be snapped together and apart, but also fix the lock members to the head  17 . Each lock member  235  is generally channel shaped, and includes lower wall sections  245  having inner edges  247  inclined relative to the center line C of the leg. As best seen in  FIG. 32 , the edges  247  converge toward the center line C from the lower end of the lock members  235  upward. As the wedge  237  is drawn up into the lock members  235 , the sides of the wedge engage the inclined inner edges  247  of the lower wall sections  245  so that the lower ends of the lock members are forced apart. 
   The lock members  235  are also positively drawn together by action of the wedge  237  in the unlock position of the locking device  228 . In that regard, an upward extension of the wedge  237  is formed with undercut cams  248  engageable with respective lock members  235  to pull them toward each other in the unlock position. Each of the lock members  235  has a roughly channel shaped construction, with the open portion of each channel facing the open portion of the opposite lock member channel. In a mid-section of the lock members  235 , ramps  249  project inwardly from the sides of the channel toward each other. These ramps  249  are received under the undercut portions of the cams  248  such that they are captured by the cams. The ramps  249  angle inwardly from the bottom to the top of the lock member mid-section. Thus, it will be understood that as the wedge  237  is moved down from the position shown in  FIG. 32A  by depressing the button  229 , the cams  248  move along the ramps  249  drawing the lower portions of the lock members toward each other, as shown in  FIG. 32B , and away from the inner surface of the second leg section  25 . The wedge  237  moves down so that only a thinner portion of the wedge remains between the lock members  235 , allowing the lower portions of the lock members to move toward each other. The action of the cams  248 , and centering of the rod  233  and wedge  237  in the second leg section  25  facilitate complete disengagement of the lower portion of the locking device  228  from the second leg section. Thus, the leg section  23 ,  25  slide freely relative to each other and wear on the locking device  228  is reduced. 
   The lock members  235  are configured so that only lower portions of the lock members move under influence of the wedge  237 . A hinge  250  is formed at a location of each lock member  235  where sides of the channel are cut away and the remaining wall is thinned (see  FIG. 31A ). Thus, the lower portion of each lock member  235  may pivot about an axis perpendicular to the longitudinal axis of the leg  19  between the lock and unlock positions. The lower portions are farther away from each other in the lock position and closer together in the unlock position. An engagement portion of each lock member  235  for engaging the inner surface of the second leg section  25  to grip the second leg section and lock the first leg section  23  in a fixed position of extension relative to the second leg section is defined by a resilient member (generally indicated at  251 ) overmolded onto the lower portion of the lock member. The resilient member  251  is formed of a softer elastomer and has a first or upper edge  251 A and a second or lower edge  251 B. The resilient member  251  tapers in thickness from its center toward the edges  251 A,  251 B. In other words, a thickness T1 at the center of the resilient member  251  is greater than the thickness T2 at the edges  251 A,  251 B. It is to be understood that the thickness edge  251 A,  251 B does not have to be the same. This curvature of the resilient member  251  reduces wear of the resilient member. However, wear can be accommodated by rotating the screw  232  as mentioned above to move the wedge  237  nearer to the button  229  so that the lock members  235  are driven further apart by the wedge in the lock position. The locking device  228  is also capable of automatically compensating for wear of the resilient members  251  which will occur over time. The inclined inner edges  247  of the lower wall sections  245  and the sides of the wedge  237  interact to drive the lower portions of the lock member  235  further apart as the resilient members  251  wear to assure continued tight gripping of the second leg section  25  in the lock position. In other words, the wedge  237  is drawn farther into the lock member as the resilient members  251  wear. 
   In addition, each resilient member  251  has laterally extending serrations  252  which facilitate both the gripping action of the resilient member with the inner surface of the second leg section  25  and the release from the second leg section. Gripping is enhanced because in the lock position any moisture between the resilient member  251  and the inner surface of the second leg section  25  can be channeled to the sides of the resilient member and out from between the two surfaces so that it does not interfere with gripping. Release is facilitated because the soft elastomer of the resilient member  251  has a tendency to cup and form a vacuum between the resilient member  25  and the inner surface of the second wall, making release difficult. The serrations  252  break the vacuum because they communicate air from the side of the resilient member  251  so that a vacuum is not drawn. 
   It is envisioned that frictional engagement portions other than the resilient members  251  could be used, such as multiple O-rings (not shown) received around both lock members  235 . In that case, the O-rings could also serve to bias the lock members  235  to the unlock position. A separate spring or the like (not shown) could be used to bias the lock members  235  toward each other for positive release disconnect in the unlock position. Each lock member  235 , including the upper and lower portions, the ears  107 , lower wall sections  245 , ramps  249 , is molded as one piece from low friction material, such as nylon or another polymer. Molding from one piece eliminates relative movement and possible loss of alignment between parts of the lock members  235  which otherwise helps to assure complete disengagement of the resilient members  251  from the inner surface of the second leg section  25  in the unlock position. Use of a synthetic material having a low coefficient of friction, such as nylon, allows the ears  107  to freely slide along the interior of the second leg section  25 . It is to be understood that these could be formed as separate pieces without departing from the scope of the present invention. 
   Having described the construction of the locking device  228 , its operation to lock and unlock the first and second leg sections  23 ,  25  will now be described with reference to  FIGS. 33 and 34 . Normally, a spring  257  located above an annular shoulder  259  in the cap  157  of the leg  19  biases the button  229  and rod  233  attached thereto upward (as indicated by the arrow) along the center line C of the leg to the lock position. Although the spring  257  is located in the cap  157  and is received into a passage in the button  229 , the spring may be located anywhere along the length of the rod  233  without departing from the scope of the present invention. The wedge  237  is drawn into the lock members  235  by the spring  257  and the sides of the wedge engage the inclined inner edges  247  of the lower wall sections  245 . The lower portions of the lock members  235  are forced apart (as indicated by arrows) so that the resilient members  251  grippingly engage the inner surface of the second leg section  25  (see also  FIG. 32A ). In this lock position, the first and second leg sections  23 ,  25  are held against telescoping movement to extend or retract the leg  19 . 
   To unlock the leg sections  23 ,  25 , the button  229  is depressed (as indicated by the downward arrow in  FIG. 34 ) forcing the button and rod  233  down against the bias of the spring  257 . The wedge  237  moves down and partially out from between the lock members  235 . At the same time, the cams  248  slide down the ramps  249  drawing the lower portions of the lock members  235  together and disengaging the resilient members  251  from the inner surface of the second leg section  25  (se also  FIG. 32A ). This action does not rely on any material retaining its resiliency over a period of time as the cams  248  pull the lock members  235  to the unlock position every time. The guide openings  244  in the upper guide portion of the locking members  235  center the rod  233  and lock members so that the resilient members  251  disengage the inner wall of the second leg section  25 . The first and second leg sections  23 ,  25  are free to slide relative to each other without interference from the locking device  228 . 
   As shown in  FIG. 34 , a cavity  261  in the cap  157  in which the button  229  is received is wider than the button, permitting some side-to-side movement of the button within the cavity relative to the cap. A catch  263  formed on the cap  157  generally adjacent to the cavity  261  opens on one side toward the button  229 . A toe  265  formed on the lower end of the button  229  can be inserted into the open side of the catch  263  by moving the button sideways in its fully depressed position ( FIG. 34 ). The force of the spring  257  holds the toe  265  in the catch  263  so that the locking device  228  is retained in the unlock position without continuing to apply thumb pressure to the button  229 . The toe  265  and underside of the catch  263  are angled upwardly to enhance retention of the button  229  in the unlock position. The first and second leg sections  23 ,  25  are thus freely movable relative to one another without holding the button  229  down. By moving the button  229  sideways away from the catch  263 , the toe  265  can be removed, and the locking device returned to the lock position of  FIG. 33 . The manipulations necessary to engage the button  229  with the catch  263  to hold it in the unlock position and to release the button from the catch can be performed with the thumb of one hand. However, other ways of manipulating the holding the locking device  228  in the unlock position may be employed without departing from the scope of the present invention. 
   Mounts  35 ,  35 A,  35 B,  201  of the present invention have previously been described in association with the foot ( 27 ,  27 A,  27 B), the joint of the leg sections  23 ,  25  and in the context of mounting the support(s) to the surveying pole  3 . These mounts permit a tongue in groove connection, or a bolted on connection, or both. It to be understood that the mounts do not need to be capable of accepting both bolted and tongue in groove connections. Referring to  FIG. 35 , a first and a third embodiment of modular mounts are shown, including the fixed mount  201  and a selectively positionable mount  267 A. The mount  201  located at the upper end of the lower pole section  7  was partially described in regard to attachment of the support  1  to the pole  3 . Mount  201  includes a tubular body  269  permanently attached to the surveying pole  3  such as by gluing. The mount  201  is shown separate from the surveying pole  3  in  FIG. 36 . It may be seen that in addition to the mounting formations  203  and bolt holes  271 , the mount  201  incorporates spaced apart posts  273  which attach the clamp  9  used to fix the axial position of the upper and lower pole sections  5 ,  7 . However, such additional structure is not necessary to the present invention. 
   A selectively positionable mount  267  (see  FIG. 37 ) of a second embodiment includes a tubular body  277 , mounting formations  279  having bolt holes  280  like the mount  201  of the first embodiment. However, the internal diameter of the positionable mount  267  is larger than the diameter of the lower pole section  7  so that the body  277  may slide onto and along the lower section. The upper end of the tubular body  277  is threaded and has four axially extending slots  283  which permit the threaded portions of the body to flex inwardly relative to the remainder of the body  277 . A compression nut  285  has a central opening  287  larger than the diameter of the lower pole section  7 . Threads formed internally of the compression nut  285  are diametrically closer at the top end of the nut than at the bottom, thereby forming a wedge. When screwed onto the upper end of the tubular body  277 , the compression nut  285  forces the threaded portions to bend inwardly into gripping engagement with the lower pole section  7  to releasably fix the positionable mount  267  on the lower pole section. 
   The mount  267 A constitutes a third embodiment of the mount, and is shown in  FIGS. 38 ,  38 A and  39 . The mount  267 A has threaded portions at both ends of the tubular body  277 A and a second compression nut  285 A for screwing onto the lower threaded portion for more secure attachment. The tubular body  277 A of the mount  267 A is formed of two semi-cylindrical parts  286 A capable of being fitted together. Each body part  286 A receives a circumferential portion of the pole  3 . It is to be understood that the mount  267 A could be formed as a single piece, or in more than two parts within the scope of the present invention. As shown, the parts  286 A are identical to each other. Each body part  286 A includes four tubular projections  288 A which can be received in openings  280 A of the opposite body part. A loose connection may be achieved in this manner. The parts  286 A are secured together by the compression nuts  285 A which simultaneously secure the mount  267 A to the pole  3 . The projections  288 A of only one of the parts  286 A can be seen in  FIG. 38A , the other body part having projections in registration with the bottom four openings  280 A of the body part on which the projections  288 A can be seen. The projections  288 A and openings  280 A are capable of receiving bolts (not shown) or the like through the mounting formations  279 A for mounting items on the modular mount  267 A. 
   A modular mount  267 B of a fourth embodiment shown in  FIG. 38B  is of similar construction to the modular mount  267 A of the third embodiment. Corresponding parts of the modular mount  267 B will be indicated by the same reference numbers as for  267 A, but with the suffix “B”. The modular mount  267 B comprises a tubular body  277 B having two parts  286 B and  286 B′. Unlike the parts  286 A of the third embodiment, the parts  286 B and  286 B′ are not identical. Instead, the part  286 B′ has a socket member  294 B which is like the socket member  341  described hereinafter in relation to  FIGS. 52 and 53 . 
   The fifth embodiment of the mount is shown in  FIG. 38C  and designated generally at  267 C. The modular mount  267 C is of similar construction to the modular mount  267 B of the fourth embodiment. Corresponding parts of the modular mount  267 C will be indicated by the same reference numbers as for  267 B, but with the suffix “C”. The modular mount  267 C differs from the mount  267 B in that in place of the socket member  294 B, a level vial holder  13 C is formed on part  286 C′ of the modular mount. It will be understood that various forms of mounts or other structures may be formed on modular mounts (not shown) without departing from the scope of the present invention. 
   Some uses of these modular mounts are shown in  FIGS. 40 and 41 . In  FIG. 40 , the fixed mount  201  attaches the bipod support  1 , the single leg support  221  and a data collector  289  at the same level. Moreover, a battery pack  290  is mounted on the positionable mount  267 . Batteries  292  held in the pack  290  are shown exploded from the pack in  FIG. 40 . The articles are exemplary only, as other articles could be mounted in a similar fashion. The level  13  is shown mounted on the surveying pole  3  independently of the modular mounts  201 ,  267 . However, as shown in  FIG. 41 , a modified level  13 A can be constructed for tongue in groove connection to the mounting formation  279 A of the modified positionable mount  267 A. A walkie talkie  291  can be attached by tongue in groove connection to the mounting formation  279 A on the opposite side. Meanwhile, the data collector  289  and a battery pack  290  can be bolted to the mount  267 A. In this case, the battery pack  290  includes an attachment member  293  formed with internally threaded holes (not shown) which threadably receive the ends of the bolts  295  passing through an attachment member  297  of the data collector. Thus, it may be seen that up to four items can be mounted at the same height on the surveying pole  3  with the embodiments of the modular mounts  201 ,  267 ,  267 A illustrated. 
   An adjustable support for a data collector case is shown in  FIGS. 42-44  to comprise an attachment member  299  attached by bolts  301  ( FIG. 43 ) to the fixed mount  201 . A cylinder  303  projects outwardly from the attachment member  299  and receives a sleeve  305  of a bracket (generally indicated at  307 ) thereon. The bracket further includes a channel  309  having an open upper end and a closed lower end ( FIG. 44 ) for receiving a slide  311  attached to a data collector case  313  through the open end into the channel to connect the case to the bracket  307 . The cylinder  303  has a relatively large diameter in relation to its length, for example the length of the cylinder may be 1½ inches and its diameter 1 7/16 inches. It is noted that the length of the body  269  of the fixed mount  201  helps to distribute loads over the larger surface area of the lower pole section  7 . 
   The position of the bracket  307  about the axis of the cylinder  303  can be changed by turning the bracket on the cylinder. To secure the bracket  307  in selected angular position, first sets of detents  315  are provided on the ends of the sleeve  305  and a second set of detents  317  is provided on the attachment member  299  extending circumferentially around the cylinder  303 . A cap screw  319  may thread into a central threaded opening  321  of the cylinder  303  and be screwed into the cylinder. A flat, smooth underside of the head of the cap screw  319  engages one edge of the sleeve  305  and forces it against the attachment member  299 . The detents of one of the first sets of detents  315  engage with the second set of detents  317  on the attachment member  299  to lock the bracket  307  in a fixed angular position. Unscrewing the cap screw  319  releases the first and second sets of detents  315 ,  317  from meshing, allowing the angle of the bracket  307  to be changed. By providing a first set of detents  315  on both ends of the sleeve, the bracket  307  can be placed on the cylinder  303  in either direction and still be capable of locking in selected angular positions. 
   A modified form of the attachment member and cylinder  303 A are shown in  FIGS. 45 and 46 . The attachment member has the form of an elastic clip  299 A which can snap onto a modified fixed mount  201 A in a circumferential channel  275  separating mounting formations  203 A on each side into two parts. The clip  299 A allows for more rapid attachment (and disconnection) of the cylinder  303 A. Thus, the cylinder may be readily moved from one side of the fixed mount  201 A to the other. 
   A connection system of the present invention is shown in  FIGS. 47-51 . The system includes a first connector  325  which is fixed to an article (e.g., a walkie talkie). The article is not shown in  FIG. 47  for clarity. A second connector is not shown in  FIGS. 47-51  but can be of the same general construction as the bracket  307  in as much as the bracket includes a channel having a floor, side walls and inwardly turned lips extending toward each other over the floor. A third connector  327  ( FIG. 47 ) has a back  329  and a generally U-shaped receiver  331  having an open upper end. The third connector  327  may be attached to an object other than the surveying pole  3  such as a bag, another piece of equipment or an piece of clothing (not shown). The first connector  325  includes two connector components, a circular undercut slider  333  and a rectangular undercut slider  335  aligned so a longitudinal axis of the rectangular slider passes through the center of the circular slider. These components are shown in hidden lines in  FIG. 47  because they are on the opposite side of the first connector  325 . The diameter of the circular slider  333  is about the same as the width of the rectangular slider  335 . When attached to the second connector (e.g., bracket  307 ), both the circular slider  333  and rectangular slider  335  are received in the channel (e.g., channel  309 ) with their undercut portions capturing the lips of the channel. To attach the first connector  325  to the third connector  327 , the first and third connectors are turned so that the circular slider  333  is lined up with the open upper end of the U-shaped receiver  331  and the rectangular slider  335  is positioned to one side of the U-shaped receiver. The first connector  325  may then be moved so that the circular slider  333  only is received in the U-shaped receiver  331 . The first connector  325  may then be rotated so that the rectangular slider  335  moves to a position under the U-shaped receiver. This configuration is illustrated in  FIGS. 48 and 49 . Modified forms of the third connector  327 A,  327 B are shown in  FIGS. 50 and 51 . A back  329 A of the receiver  327 A does not extend across the “U” in the version shown in  FIG. 50 . Slots  337  on either side of the U-shaped receiver  327 B can receive, for instance a belt (not shown) worn by a person. Thus, an article can be removed from the bracket  307  on the surveying pole  3  and attached to the belt quickly and easily. 
   A modified form of connecting an article such as the data collector case  313  to the modified mount  201 A is shown in  FIGS. 52 and 53 . The modified version includes a socket member  341  extending outwardly from an attachment member  343  (of substantially the same construction as the attachment member  299 ). The socket member  341  includes a central hole  345  and multiple locator holes  347  extending in a circle around the central hole. The central hole  345  can receive a peg  349  attached to a C clamp holder  351  capable of gripping the case  313 . The peg  349  has a circumferential groove  353  near its distal end which receives the end (not shown) of a hold pin  355  inside the socket member  341  to prevent inadvertent withdrawal of the peg from the socket member. A small stud (not shown) on the side of the C clamp holder  351  is selectively received in one of the locator holes  347  around the central hole  345 . The angular position of the C clamp holder  351  and the case  313  is selected by choosing the locator hole  347  into which the stud is inserted. A further modified version of the socket member  341 A and attachment member is shown in  FIG. 54 . As with the version shown in  FIGS. 45 and 46 , the attachment member  343  is replaced by an elastic clip  343 A for snap on connection to the fixed mount  201 A. 
   Referring now to  FIGS. 55-63 , a foot assembly of a second embodiment is designated generally at  356 , and shown mounted on the lower end of the second leg section  25 . The foot assembly  356  includes a receptacle  360  for receiving a lower end of the second leg section  25  onto a boss  365  at the bottom of the receptacle ( FIG. 57 ) to orient and locate the foot assembly relative to the second leg section. Pan head screws  358  are received through respective openings  359  to secure the foot assembly  356  to the second leg section  25 . A foot pad  361  formed as one piece with the receptacle  360  is used to apply foot pressure to drive the foot assembly into the ground. Two generally triangular webs  363  located under the foot pad  361  are arranged perpendicularly to each other in a “T” pattern. The webs  363  strengthen the foot pad  361  and provide stability as will be described. 
   The foot pad  361  has a counterbore  362  extending through it which receives a screw  357  used to secure the foot assembly  356  (and hence the support) to the ground. The foot assembly  356  is able to engage a variety of terrain surfaces of different densities. These commonly encountered terrain surfaces include concrete, asphalt, frozen ground, ice, loose soil, mud and sand. Stability of the survey support system is best achieved by a positive connection of the support with all of these varying terrains. More particularly, the foot assembly  356  should connectively resist several forces including upward/extraction of the foot and also side-to-side rolling (pivoting about the axis of the second leg section  25 ). The greatest force to resist is found in compression and tension along the centerline of the leg. Differing densities of the variously engaged terrains necessitate significantly differing sized bearing surface areas to attain the same degree of stability. The present invention provides penetration and sufficient bearing on all these surfaces. For instance, on asphalt or ice, sufficient bearing surface is provided solely by the screw&#39;s penetration, because a positive (threaded) connection with those surfaces can be made. However, on loose soil or sand where no positive connection can be made by the screw  357 , a much larger bearing surface is provided by the webs  363  and underside of the foot pad  361 . 
   Screw  357  may be a standard manufacture, metal screw-type masonry fastening anchoring product that is commercially available and is typically used to attach objects to masonry and concrete substrates. A suitable example of these fasteners is produced by Illinois Tool Works, Inc. of Glenview, Ill. and is marketed under the mark “TAPCON”. In the case of survey supports, some terrain surfaces that are encountered are particularly hard and abrasive. The screw  357  still provides an advantage even though it may not make a threaded engagement with the surface. The screw is hardened and exceptionally resistant to wear. However, should wear ultimately occur, the exposed length of screw  357  below the foot may be advanced to accommodate some abrasive wear. Since the screw  357  is of standard manufacture and is widely available, field replacement of the screw itself is also possible. In fact, screws of the same type and diameter, but of different lengths are also available and therefore allow further adaptation of the support to specific field conditions. 
   Field adjustment of the exposed length of screw  357  (i.e., the length of the screw projecting below the bottom of the foot assembly  356 , see  FIGS. 57 and 59 ) is anticipated. To provide for unobstructed adjustment, counterbore  362  is sized to receive screw  357  and a screwdriver (not shown) to allow for adjustment. A smooth upper portion  364  of the counterbore  362  receives the head of the screw  357  below an upper surface of the foot pad  361  and allows selective adjustment of the screw. The lower portion of the counterbore  362  threadably engages the foot assembly  356  so that rotation of the screw  357  produces extension from or retraction into the counterbore. A washer  366  formed integrally with the screw  357  at the based of the screw head is sized to closely fit within counterbore  362  while still allowing movement of the screw within the counterbore. The close fitting relationship between the screw washer  366  and counterbore  362  forms a seal and prevents dirt and debris from entering a spaced between the underside of the washer  366  and the bottom of the smooth upper portion  364 . Thus, dirt and debris will not limit the amount of adjustment of the screw  357  which can be made. 
   Screw  357  may be used in several different ways to secure the foot to the underlying ground or other surface. In the instances of use on hard, but rough terrain surfaces and when the support is used only to assist the user in steadying the support, only the point of the screw is required to contact the terrain surface. The point is sharp and opposes the compressive forces on the leg of the support. In other instances of use on moderately hard terrain surfaces such as frozen soil, asphalt pavement and ice, the screw  357  can be selectively extended to increase the depth of penetration into the surface. The greater extension of the screw  357  to provide a greater depth of terrain surface penetration is illustrated in  FIG. 59  and  FIG. 60 . The foot assembly  356  is thrust into the terrain by the user&#39;s foot pressure applied by stepping on the foot pad  361  so that not only the exposed portion of the screw  357  penetrates the surface, but at least a portion of the webs  363 . In this use, the threads of screw  357  are thrust into the terrain without rotation and contact the terrain to provide a barbed, resistive connection in these dense surfaces. Further stability is offered by the flat web surfaces  371 . These surfaces offer resistance to forces tending to unseat the foot because of the orientation of the webs  363  and the surface areas available to distribute the loads applied through the legs  19 ,  21 . The orientation of the webs  363  relative to the remainder of the leg  19  will provide surface areas which are not parallel to the applied loads. With the resulting increase in area for absorption of the applied loads, significant resistance to the forces tending to move the foot is generated. 
   When the support is used on hard terrain surfaces and is exposed to wind or other destabilizing forces, another method of use is possible. The method in such case requires the creation of a hole in the hard terrain substrate surface as illustrated in  FIG. 62 . In this method, screw  357  is first retracted fully into the foot  356 . A pilot hole  370  is drilled into a concrete or masonry substrate having size approximately equal to the minor diameter of the screw  357  and depth sufficient to accommodate the fully extended length of the screw. The foot assembly  356  is aligned over the hole  370  and the screw  357  is rotationally advanced into the hole ( FIG. 62 ). The threads of the screw  357  directly engage the concrete or masonry substrate in the hole  370 . The screw  357  is advanced by rotation so that the washer  366  formed as one piece with the head of the screw (at its base) engages the bottom of the smooth portion  364 . Further advancement of the screw  357  pulls the foot assembly  356  downwardly against the substrate (e.g., the concrete surface illustrated in  FIG. 62 ). When screw  357  is fully advanced, the threads of screw  357  connectively engage both the substrate hole surface  370  and also the surfaces of counterbore  362 , thus forming a positive connection of the support to the concrete. While surveyors and other users of geomatic supports normally do not install concrete screws, they do typically posses and use hole generating tools such as star-drills or cordless hammer drills to produce holes in concrete surfaces for the mounting of survey monuments, pins and markers. Additionally, these same users also typically possess screwdriver tools of the same type as required to engage screw  357 . These same hole-generating capabilities and screwdrivers thus may be conveniently utilized and applied to provide receptacle holes and to engage screw  357  in the above described manner. 
   Use of the support in less dense terrain surfaces such as soil, sand and mud are also anticipated. In instances of engaging less dense terrain surfaces such as soil or sand, screw  357  alone does not provide sufficient connective resistance required for stability on the support. To provide sufficient connective resistance on these less dense surfaces, the webs  363  of the foot  357  are also provided. In use, these webs  363  are downwardly thrust into the substrate terrain to substantially their full height. To facilitate downward penetration in the terrain, these webs  363  are formed in a cross shape in order to provide a small cross-sectional surface. Terrain penetration is further facilitated by foot pad  361  wherein the user applies his or her weight to insert the foot  356  into the terrain. The broad surfaces of the webs  363  however are arranged to provide bearing surfaces which are perpendicular to each other to enhance resistance to the forces of the leg in maintaining stability of the support. 
   Insertion of the foot into less dense terrain can be difficult for the user as the foot can tend to rotate in response to uneven resistance in the substrate terrain. For instance, one side of the foot can encounter a small rock while the other encounters only soil. Rotation of the foot (about the axis  367  of the leg  25 ) is undesirable, as the webs must be fully planted in order to provide optimum stability resistance to forces. To resist this rotational effect, several features are combined. For one, the foot pad  361  is formed in a shape that is wider than the distance from the foot pad  361  to the line of contact with the terrain (e.g., the width of the foot pad is greater that the height from the foot pad to the distal surface  371  of the webs  363 ). The contact area of the foot pad  361  encountered by the users shoe tends to cause the webs  363  to remain perpendicularly aligned during insertion. Further, the flat surfaced sides of webs  363  tend to guide insertion once they penetrate the terrain. An additional feature is the contact line  371  formed at the distal ends of the webs. The width of the contact line tends to further distribute and balance the forces of insertion of the webs  363  as they penetrate the terrain. The contact line  371  tries to engage the ground over its whole length tending to cause the foot to square up before penetrating the ground. 
   When used on hard terrain surfaces such as concrete, instability of the support can also occur if the legs  25  rotate about their centerlines. In these conditions, the hard terrain surface tends to allow only a point contact of the foot. This rotation can occur due to an offset of the point of contact of the foot to the terrain in relationship to the centerline of the leg. The foot assembly  356  of the present invention is formed so that its point of contact with the underlying surface is coplanar with the centerline  367  of the leg to reduce the tendency of the foot assembly  356  to rotate as it is being forced into the ground. However, the foot assembly  356  is also constructed so that the foot pad  361  and webs  363  are not coaxial with and are arranged at an angle to the centerline  367  to resist compressive and extensive forces applied by the second leg section  25  to the foot assembly. 
   When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. 
   In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained. 
   As various changes could be made in the above constructions without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.