Patent Publication Number: US-6702509-B2

Title: Scaffold clamp

Description:
FIELD OF THE INVENTION 
     The present invention relates to scaffold clamps and in particular relates to scaffold clamps with improved functionality. 
     BACKGROUND OF THE INVENTION 
     Scaffold clamps or scaffold couplers have been used for many years to structurally connect scaffold tubing in a simple manner. Many scaffold clamps comprising various components which are formed or bent to a desired shape and then welded to other formed components. These clamps include a closable latch member for closing around and releasably engaging a scaffold tube. Typically, an adjustable fastener is provided for drawing the scaffold clamp into engagement with the tube. Some scaffold clamps use a captured wedge to simplify securement of the clamp to a structure. As can be appreciated, scaffolding systems are assembled for a temporary purpose and the fast assembly as well as fast release are important characteristics for a clamp. 
     Many of the scaffold clamp systems available today are prone to damage and typically it is not cost effective to repair the clamp due to the design thereof. Also many scaffold systems are rented or leased and as such subject to additional abuse. 
     It is also desirable with respect to the scaffold clamps that the clamp be easy to use and fast to secure in different orientations. Scaffolding systems are temporary structures and therefore speed of fastening of the clamp, as well as removal of the clamp is important. In cold climates, it is important to have a clamp which does not require a lot of dexterity as the workman may be wearing gloves. 
     SUMMARY OF THE INVENTION 
     A scaffold clamp according to the present invention comprises a body portion, two pivotting latches attached on opposite sides of the body and two recess sockets, each socket having a slot opening therein. A fastener is located in each of the slot openings of a socket. Each fastener has a shank which passes through the recess and is movable within the recess and the shank has a captured wedge member on one side of the slot and a bolt head oversized relative to the slot, on the opposite side of the slot. 
     With this arrangement, the fastener is captured on the body portion with the bolt head on one side of the slot and the wedge on the opposite side of the slot. The body portion includes on opposite sides thereof, support recesses which cooperate with the associated latch to form a generally circular scaffold support engaging recess. The latch and wedge cooperate with the body portion to adjust the size of the circular engaging recess by movement of the wedge relative to a wedge receiving slot on the respective latch. 
     In a preferred embodiment, each latch includes a wedge receiving slot which acts as a guide for the wedge. 
     In a preferred aspect of the invention, each bolt head is positionable to be fully received within the associated recess socket of the body portion and rotatable about the axis of the shank within the recess socket. 
     In a further aspect of the invention, the recess sockets are located within the support recesses. 
     In yet a further aspect of the invention, an edge portion of each recess socket forms a peripheral edge portion of one of said support sockets. 
     In a further aspect of the invention, the support socket includes a series of engaging ridges extending across the support socket. 
     In a further aspect of the invention, each fastener is rotatable within the associated socket recess between a release position where the fastener extends away from the latch to an engaging position where the fastener passes through the latch. Each socket recess has sufficient depth to accommodate movement of the associated fastener between the release position and the engaged position while maintaining the bolt head within the confines of the socket recess. 
     In a different aspect of the invention, each shank includes an elongate slot recess in which the associated pivotting wedge slides. Each pivotting wedge at a narrow end thereof includes a releasable stop which blocks the wedge from passing through the elongate slot recess and a wide end which is larger than the elongate slot recess such that the wedge is captured on the fastener. With this arrangement, the wedge can be replaced by release of the stop and insertion of a new wedge which is then captured by the associated releasable stop. 
     In a preferred embodiment of the invention, the stop is a replaceable component fixed on said wedge. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are shown in the drawings, wherein: 
     FIG. 1 is a partial perspective view of the scaffold clamp; 
     FIG. 2 is a sectional view showing the scaffold clamp engaging two scaffold supports; 
     FIG. 3 is a perspective view showing the scaffold clamp engaging one scaffold support and about to engage a perpendicular scaffold support; 
     FIG. 4 is a partial perspective view showing opening of one latch and movement of the fastener to a second position for securing of the clamp; 
     FIG. 5 is a partial perspective view of the clamp and engagement with two scaffold supports. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The scaffold clamp  2  shown in the drawings has a body  4  with recessed sockets  6  located approximately 90 degrees from one another and opening in opposite directions. Each of these recess sockets include a slot opening  8  which allows movement of the fastener  10  from a release position as shown in FIG. 1 to the engaged position as generally shown in FIG.  5 . The body  4  is preferably one piece. 
     The fastener  10  has a bolt head  16  at one end of the shank  12  and a captured wedge  14  passing through an opposite end of the shank. The shank  12  has a closed slot  18  for receiving the generally flat captured wedge  14 . The shank  12  is enlarged adjacent the slot  18  and is shaped such that it can only enter the slot  28  associated with the latch  24  in one of two orientations which orientations are 180 degrees apart. For example, the shank as shown in FIG. 1 is in one position, and if the latch  24  is brought to the closed position, the shank can be rotated and will enter into slot  28  to assume a position as shown in FIG.  3 . Thus, the fastener  10  is free to rotate about the axis of the shank with the bolt head within the recess socket. 
     The second orientation requires the shank to be rotated about the axis of the shank 180 degrees to bring the wedge  14  to a position above the shank and then the shank is inserted into slot  28 . If this rotation was to occur, the wedge as shown in FIG. 3 would actually be with the wedge positioned for downward engagement with the latch. As such the fastener  10  is reversible for engaging movement of the wedge in one of two directions 180° apart. 
     The latch  22  is pivotted on the lug  40  and is moveable from a fully opened position as shown in FIG. 1 to a closed position as generally shown in FIG.  2 . The captured wedge  14  is moveable from an initial position as generally shown in FIG. 3 to an engaged position by moving of the wedge upwardly such that the wedge  14  engages the receiving grooves  30  provided on the fastening flange  26 . The grooves  30  serve to guide and retain the wedge on the fastening flange and avoid any possibility of the wedge sliding off the edge of the fastening flange. These grooves also locate the wedge relative to the latch and assure the wedge draws the latch into engagement with the scaffold support  50   a  or  50   b.  The wedge when appropriately driven by a hammer has an interference fit with the grooves and thus will retain the wedge in the fixed position. Thus the wedge can be driven upwardly when necessary to a locked position. Typically the fastening member is rotated such that the wedge can be driven downwardly to a fastened position. 
     It can be appreciated that there are certain circumstances where an upward movement of the wedge is required, often where there is a top interference condition. 
     The captured wedge  14  includes at a narrow end  34 , a replaceable stop member  36 . This is presently shown as a nut and bolt connection but it could be an enlarged rivet or other structure which forms an interference fit with the slot  18 . This fastening member maintains the wedge captured on the shank  12 . The opposite end of the wedge is enlarged relative to the shank slot  18  and forms the opposite restricting member. As such, the wedge is captured on the shank. Other arrangements for capturing the wedge on the shank can be used. 
     The fastener  10  is rotatable within the recessed sockets  6 . This rotation can occur essentially in any position of the fastener within the slot opening  8 . For example, the fastener shown in FIG. 4 can be freely rotated about the axis of the shank to position the wedge in either an upwardly or downwardly position for engagement with the latch  22 . The bolt head  16  rotates within the recessed socket  6  and is not restricted by the support  50   a  provided at the rear of the socket  6  which effectively closes the recess socket. Therefore, if the scaffold support  50   a  of FIG. 4 is initially secured, and support  50   b  is about to be secured, the user can rotate the fastener  10  to either of its two fastening positions merely by having the fastener clear the slot  28  in the latch  22  and rotate the fastener by means of rotating the wedge. 
     Therefore, if the worker positions support  50   a , he still has full flexibility with respect to the securement of the support  50   b  without releasing securement of support  50   a . This is not the case with other fasteners where the fastener  10  would have to pass out of the socket recess  6  to allow rotation thereof. With these prior art systems, the support  50   a  would have to be released, the fastener  10  then appropriately positioned and both latches then reassembled. With the present system, each latch and the fastener thereof acts independently and has full functionality independently of the other latch. 
     It is preferred that both the one piece body portion and the latches be formed as a single piece, for example, by casting, drop forging or pressed steel manufacture. These components when made in this manner, have excellent strength and durability and can tolerate substantial abuse. In addition, if there is damage to a latch, it can be replaced merely by removing the pivot pin and installing a new latch. If there is damage with respect to the fastener, the wedge can be removed and the fastener replaced with a new fastener using the old wedge or a new wedge. Similarly, if the wedge is damaged, it can easily be replaced by removing of the fastener  36  and installing a new wedge  14 . 
     A further aspect of the invention is in the extended grip area of the clamp relative to the support tubes  50   a ,  50   b . As shown in FIG. 2, the recessed socket  6  forms part of the support recess  20  and the periphery  11  of the recess socket  6  forms one end of the support recess  20 . This is shown in FIG. 2 where the peripheral edge  11  forms the upper engagement with the support tube  50   b . It can also be seen that the one piece body also extends beneath the lug  40  and thus gripping of the tube  50   b  is distributed along a substantial portion of the tube. The support recess  20  also includes a number of ribs  41  which provide positive engagement with the support tubes. Similarly, the latch  22  includes engaging ribs  43  to provide positive engagement. These ribs assist in the mechanical engagement, reduce slippage, and provide additional flexibility regarding the precise fit. 
     The present scaffold clamp is manufactured to provide significant strength with respect to the one piece body and the latches as well as the captured wedge. The scaffold clamp has a significantly greater useful life and is also repairable in a relatively simple manner. The typical wear components are the captured wedge  14  and the fastener  10 . Each of these components, although captured on the clamp, are easily replaced. In this way, the useful life of the scaffold clamp is greatly extended. For example in a fabricated and welded clamp the life expectancy is about 4 years for rental applications whereas the life expectancy of the present clamp is much greater and in many applications will be at least 8 years. 
     The body portion  4  has been described in the preferred one piece construction suitable for securing scaffold supports in a perpendicular manner. It is also possible to use a two piece construction for the body which allows pivotting of the sockets to accommodate scaffold supports at different angles. In this case, the two pieces are pivotal about a pin which fastens the two pieces. 
     Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims.