Patent Publication Number: US-7213848-B2

Title: Spring open latch clamp

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention generally relates to manual clamps, and more particularly, relates to a manual toggle locking pull action clamp. 
   2. Description of Related Art 
   Manual clamps including pull action clamps and toggle locking action clamps have been known for numerous years. Prior art toggle clamps may include an extension of folded sheet metal riveted to both sides of a central handle housing, which has a pivoted latch element and leaf spring reacting against surfaces of the handle to preposition the latch for engaging a base mounted latch pin upon actuating the clamp handle to a clamping position. These prior art clamps are also simple to release by manual finger activation of a lever. Other prior art toggle clamps may use a locking means that include a flat leaf spring lock welded to the handle that is released by a trigger member. 
   Many of these prior art over center toggle locking action clamps are ideally suited for holding against heavy forces such as those generated in plastic molding operations or the like. These clamps are ideal for quick clamping of doors, lids, access covers on drums, containers or other vessels. Generally, these clamps work with a latch or bracket mechanism that engages a latch plate located on a door or the like. When the prior art clamps are in the open position, the latch or bracket is placed over the latch plate and then the handle is pushed in a downward motion until the clamp toggles onto an over center position. This will lock the clamp in position and lock the door or access cover to the body being clamped. Generally, the prior art clamps require two hands to operate these manual clamps. There have been some prior art clamps that have attempted to create one hand action for opening and closing of the clamps. 
   Many of these manual prior art clamps operate satisfactorily but are frequently subjected to environments of vibration, inverted positioning, and other harsh industrial environments. Therefore, many of the prior art clamps require both of the user&#39;s hands to open the clamp, i.e., one hand is needed to operate the clamp lever while the other is needed for pulling back the latch element on the clamp. Hence, there is a need in the art for an improved manual pull action clamp that is capable of one-handed operation in the work environment while also providing for an automatic retraction of a latch or bracket mechanism from the latch plate without use of the operator or user&#39;s second hand. There also is a need in the prior art for an improved manual pull action clamp. 
   SUMMARY OF THE INVENTION 
   One object of the present invention is to provide an improved clamp. 
   Another object of the present invention is to provide an improved one handed operation clamp. 
   Yet a further object of the present invention is to provide a clamp that uses a combination of a thumb tab lever and a spring to provide a novel positioning device for a bracket of the clamp. 
   Still a further object of the present invention is to provide a manual hand clamp that will hold a connecting bracket arm in a predetermined out of way position. 
   Still a further object of the present invention is to provide a more robust and economical clamp. 
   To achieve the foregoing objects, a manual clamp is disclosed. The clamp includes a base with a handle including a first and second portion. The handle is pivotally connected to the base. A pin is arranged between the first and second portions of the handle. A bracket or arm is secured to the pin. The clamp further includes a spring arranged between the handle and the pin. 
   One advantage of the present invention is that the clamp provides a new solution for one handed clamp operation. 
   A further advantage of the present invention is that the clamp uses a thumb tab in conjunction with a spring. 
   Still another advantage of the present invention is that the clamp will use a spring to hold a connecting arm or bracket in a predetermined out of way position. 
   Still a further advantage of the present invention is the reduced time to operate the hand clamp in operating environments. 
   Yet another advantage of the present invention is the one handed operation of closing and opening of the clamp according to the present invention. 
   Other objects, features and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  shows a plan view for a clamp according to the present invention. 
       FIG. 2  shows a partial plan view of a clamp according to the present invention. 
       FIG. 3  shows a top view of a clamp according to the present invention with one portion of the handle removed. 
       FIG. 4  shows a side view of a clamp according to the present invention with one portion of the handle removed. 
       FIG. 5  shows a side view of the clamp according to the present invention, with one portion of the handle removed, having the clamp in its opened position and the latch arm stored in its predetermined open position. 
       FIG. 6  shows a close up view of the spring mechanism of the clamp according to the present invention. 
   

   DESCRIPTION OF THE EMBODIMENT(S) 
   Referring to the drawings, a clamp  10  according to the present invention is shown. It should be noted that the clamp  10  as shown in the drawings, is a manual pull action toggle locking clamp. However, any other type of manual clamp such as hold down action clamps, straight line action clamps, latch action clamps or squeeze action clamps may also be used in conjunction with the accompanying disclosed invention. It should also be noted that the present invention can be used on any known toggle action clamp or cam action clamp. 
   Referring to  FIG. 1 , a manual clamp  10  according to the present invention is shown. The clamp  10  includes a base  11 . The base  11  shown in the drawings has a first  12  and second base member  14  which are similar to each other. The base members  12 ,  14  include a plurality of orifices  16  there through. The orifices  16  are used to connect the base  11  to a door, wall, or other device that is part of the clamping environment. Another set of the orifices are used to connect a handle  18  thereto. The base  11  is generally made of a steel material however any other type of metal, hard plastic, ceramic or composite may be used for the base  11  of the clamp  10 . The base  11  may be made of a single piece of steel and not have the first  12  and second members  14  as shown in the drawings. However, it is preferred to have a first  12  and second member  14  as shown in the drawings. The first  12  and second members  14  are arranged as shown in  FIG. 1 , to create the base  11  of the clamp  10 . The base members  12 ,  14  generally have an L-shape. The base  11  may also include an upturned flanged or edge  20  on one portion thereof. The base members  12 ,  14  generally are arranged back to back to one another. However, it should be noted that the base members  12 ,  14  may be welded together or have any other type of chemical or mechanical bond used to hold the base members  12 ,  14  together. 
   The handle  18  is pivotally connected to the base  11  via an orifice  16  in the base  11  and an orifice  22  in the handle  18 . A fastener  24  is used to connect the handle  18  to the base  11 . The handle  18  is connected to the base  11  such that it pivots or rotates about the fastener  24  such that the handle  18  rotates with respect to the base member  11 . In one embodiment a rivet  24  is used, however a pivot pin, dowel, rod or the like may also be used as a fastener or pivot connection  24 . 
   The handle  18  is generally made of a steel material however any other metal, plastic, hard ceramic, or composite may be used for the handle  18 . The handle  18  includes a first  26  and second member or portion  28 . The first and second member  26 ,  28  of the handle  18  each individually include an outward extending rigid portion  30 . When the two members  26 ,  28  of the handle  18  are used in the clamp  10 , as shown in  FIG. 1 , they are placed in a side by side manner such that the outward extending rigid  30  of each handle member  26 ,  28  will in part define an interior space between the first and second members  26 ,  28  of the handle  18 . The first and second members  26 ,  28  of the handle  18  are arranged around the first and second members  12 ,  14  of the base  11  such that the inner surface of the first and second members  26 ,  28  of the handle  18  contact the outer surfaces of the base members  12 ,  14  at or near the pivot point connection  24 . The handle  18  includes a plurality of orifices therethrough. One set of orifices is aligned and used to connect with the base  11  while the other set of orifices have a fastener or pin  32  arranged therebetween to help in holding the handle members  26 ,  28  securely to one another in the clamp environment. It should be noted that in one embodiment a rivet is used as the fastener  32  but any other type of rod, dowel, pin or any other known fastener may be used between the two handle members  26 ,  28 . 
   In one embodiment a soft plastic handle grip  34  is arranged on one end of the handle  18 . The handle grip  34  can be made of any number of soft materials such as rubber, plastic, composites, cloth, etc. 
   A pivot pin  36  is rotatably supported through an orifice of the handle  18 . It should be noted that in the preferred embodiment a pivot type pin  36  is used but any other cylindrical shape member, rod, dowel, or the like may be used for the pin  36 . The pin  36  is rotatable relative to the handle  18  and will allow for a pivot movement of the pin  36  within the orifice of the handle  18 . The pin  36  includes at least one orifice  38  through a diameter thereof and in the embodiment shown there is a second orifice  38 , with one orifice  38  located near each end of the pin  36 . In one embodiment the pin  36  is made of a steel material, however any other type of metal material, hard plastic, ceramic, or composite may be used for the pin material. The pin  36  has a projection  40  extending from a surface thereof. The projection  40  generally has the form of a small dowel, rod, pin, cylindrical member or the like. However, it should be noted that any other shape member may be used for the projection  40  extending from the surface of the pivot pin  36 . The projection  40  is arranged on the surface of the pivot pin  36  such that it is located between the first  26  and second member  28  of the handle  18 . The pivot pin  36  is capable of 360° rotation within the handle  18  of the clamp  10 . 
   A latch or bracket  42  is secured to the pivot pin  36  through the orifices  38  in the pivot pin  36 . The latch or bracket  42  may have any known shape or configuration that is capable of use in the clamping environment. In the embodiment shown, a U-shaped latch bracket  42  is used. The latch bracket/arm  42  in the embodiment shown is a U-bolt that has threads on the ends thereof. The latch bracket  42  is connected to the pivot pin  36  via any known fasteners  44  or any other type of mechanical or chemical connecting means. The U-shaped bracket  42  will pivot with respect to the handle  18  of the clamp  10 . In the embodiment shown the latch bracket  42  is made of a steel material, however any other type of metal, hard ceramic, plastic, composite or other durable strength material may be used. It should be noted that a latch arm  42  may be connected to just one end of the pivot pin  36  and include a hook or other type of end and not have the U-shape as shown in the Figures. 
   A latch plate  46  is located on a door or work piece to be held by the clamp  10  in the work environment. The latch plate  46  generally has a U-shaped cross section. The latch plate  46  also includes a notch  48  near a top end thereof which will interengage and contact the end of the latch bracket  42  from the clamp  10 . The latch bracket  42  will be placed over the latch plate  46  such that the latch bracket  42  contacts the notch  48  of the latch plate  46  and when the clamp  10  is put in a fully closed or over center position the latch bracket  42  will become firmly engaged to the latch plate  46  thus securing the door or work piece being held in the clamping environment. The latch plate  46  is connected to the door or work piece via any known fastener. 
   A thumb tab or lever  50  is arranged around at least one end of the latch bracket  42 . The thumb tab  50  generally has an L-shape. The thumb tab  50  includes an orifice which will be placed around one end of the latch bracket  42 . The thumb tab  50  will be secured between a fastener  44  and the pivot pin  36  on one side of the latch bracket  42 . It should be noted that a thumb tab or lever  50  may also be placed on the opposite side of the U-shaped latch bracket  42  such that a thumb tab  50  is located on each side of the clamp  10  for easy use for a left or right handed user. It should also be noted that if a single thumb tab  50  is used it may be placed on either side of the latch bracket  42  depending on if the user is a right or left handed person. The thumb tab  50  will assist in making the clamp  10  a one-handed clamp by allowing the user to use one hand to place the latch bracket  42  over the latch plate  46  before securing the clamp  10  in its closed or over locked position. 
   The clamp  10  also includes a spring  52  arranged between the fastener  32 , located between the two members  26 ,  28  of the handle  18 , and the projection  40  extending from the surface of the pivot pin  36 . In the embodiment shown a regular extension spring  52  is preferably used to secure the fastener  32  on one end and the cylindrical projection  40  on the opposite end of the spring  52 . It should be noted that any other type of spring  52  may be used including regular extension springs, torsion springs or any other type of spring known in the art. The spring  52  will be arranged between the first  26  and second member  28  in the space defined by the two handle members  26 ,  28  and the pivot pin  36 . The location of the spring  52  in the space between the two handle members  26 ,  28  will help protect the spring  52  from any damage due to environmental contaminates found in the clamp environment. This will also ensure that the spring  52  is not accidentally removed or damaged by the user&#39;s hands and thus is not capable of being mistakeningly disengaged during operation of the clamp  10  by the user. The spring  52  will allow the latch bracket or connecting arm  42  to be held in a predetermined out of way position when the clamp  10  is in an open position. Thus, when the clamp  10  is opened the latch bracket  42  will be moved, via the spring  52 , to a predetermined holding position until the clamp  10  is reengaged with the latch plate  46  and secured into its closed position. The combination of the thumb tab  50  with the spring  52  will ensure that the clamp  10  is completely one-hand operable. The thumb tab  52  will ensure that when the clamp  10  is being put into its closed position that the operator can use the thumb tab  50  to arrange the latch bracket  42  around the latch plate  46  on the work piece being held or the door being latched. Then the clamp  10  will be closed in its usual downward motion until the handle  48  creates an over center toggle locking effect for the clamp  10 . Upon opening of the clamp  10  the spring  52  will automatically reposition the latch bracket  42  into an out of way position thus not hindering the user in any manner during operation of the clamp  10 . This will increase efficiency and speed by the user on the work line environment. It should be noted that in the embodiment shown a metal spring is used however any other type of spring such as ceramic, plastic, composite or the like may be used depending on the design requirements and the operating environment of the clamp. 
     FIGS. 1 ,  2 ,  3  and  4  show the clamp in its closed or locked position.  FIG. 5  shows the clamp  10  in an open position with the latch bracket  42  in its predetermined stored position. In prior art clamps when the clamp was in an open position or not secured to the latch plate, the latch bracket would either fall and lean on the handle or be resting on the top of the latch plate when the clamp was in an open position. With the present invention, the latch bracket  42  is held in the predetermined position as shown in  FIG. 5  by the spring  52  arranged between the fastener  32  and the projection  40  extending from the pivot pin  36 . In operation the user would take the clamp  10  from its open position, and move the handle in an upward rotating position towards the latch plate  46  until the latch bracket  42  is over the latch plate  46  and then the thumb lever  50  would be pressed in a forward direction until the latch bracket  42  engages the notch  48  of the latch plate  46 . Then the clamp handle  18  would be moved in the opposite direction away from the latch plate  46  until the pivot pin  36  and pivot point  24  between the handle  18  and base  11 , along with the latch bracket  42 , form an over center toggle locking position. When the clamp  10  is put in the over center toggle locking position the toggle action will create the greatest holding force for the clamp  10 . After the manufacturing or other operation is completed on the work piece or door being held, the user will pull the clamp handle  18  in a rotational direction towards the latch plate  46  until the over center toggle action is overcome and the latch bracket  42  disengages from the latch plate  46 . Then the spring  52  will automatically move the latch bracket  42  to the predetermined holding position when the clamp  10  is in its open position. 
   The present invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words or description rather than of limitation. 
   Many modifications and variations of the present invention are possible in light of the above teachings. Therefore, within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described.