Abstract:
A multi-clamp is illustrated which operates in the manner of a traditional “c”-clamp, but which also operates cooperatively with a support such as a pipe or bar clamp to apply forces normal to otherwise difficult or impossible to reach large sheet materials. A pair of nested u-shaped members are coupled together with a threaded rod. A knob is used to actuate the threaded rod and provide motive force or actuation between the nested u-shaped members. Two alternative embodiments are also illustrated.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to U.S. provisional patent application No. 60/383,475 filed May 23, 2002 and co-pending herewith, the contents which are incorporated herein by reference in entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention pertains generally to work holders, and more specifically to a work holder having one jaw that is common to plural coacting jaws. In a yet more specific manifestation of the invention, a clamp has a plurality of jaws that interact with at least one additional clamp or fixture to apply forces to a work surface at locations that would otherwise be impractical or impossible to reach. 
     2. Description of the Related Art 
     Mankind has, throughout the ages, used available materials in the construction of both essential and non-essential items. This construction has been so refined through the ages that many persons today depend for their entire existence upon these constructed articles. Mankind is, however, quite unique in the animal kingdom in this ability to construct so many different commodities. 
     In the manufacture or production of commodities, people use many diverse tools to simplify and enable the required processes or events to occur. Since a person is only provided with limited appendages, and these appendages can generally be applied to more useful and valuable purposes, a common need is that of ways to hold an object in place without requiring an extended application of manual force. Frequently, the object being held will be a stock material that is being acted upon in some way, such a machining, drilling, sanding, adhesively or metallurgically bonding, or any of a nearly limitless other assortment of processes and operations, as has been illustrated in the prior art and will be understood to be included herein. Objects that are relatively of the same size or smaller than a clamp or vise are frequently retained by one or more of these clamps with relative ease and simplicity. This is because the jaws of the clamp are generally within a few multiples of size of the object, and the jaws will then be capable of reaching to and apply forces at a sufficient number of points or locations on the object to achieve the desired or required application of force. 
     Unfortunately, when the object or work becomes relatively larger, the cost of purchasing and storing proportionally larger clamps frequently becomes prohibitive. Instead of trying to purchase and store such giant and bulky clamps, a person will instead rely upon more universal clamps and jigs. When these clamps and jigs are unable to apply a desired or essential force, a person will then be forced to forego the particular application, sometimes forcing full redesign of project and plans. 
     Common types of clamps include c-clamps, which are so named since the fixed jaw is formed into the general shape of the letter “C”, pipe clamps which provide jaws at indeterminate locations along an indeterminate length pipe, and bar clamps, which may be of indeterminate length but which more commonly are between pipe and c-clamps in length. These most common commercially available clamps each have only a few inches of jaw length transverse to the clamping axis, and are consequently able to grab a very limited distance onto an object. Because the length of the bar and c-clamps may be indeterminate, the spacing between jaws may be substantially larger, spanning several feet or more. This ability to adjust the jaw spacing has permitted many smaller enthusiasts or workers to keep on hand such clamps and address many of the requirements for applying force that are encountered within a work shop, irrespective of whether the shop is used for wood, metal, plastic or other stock materials or compositions. 
     Nevertheless, there has continued to be a particularly vexing problem that is all too frequently encountered. When a large sheet of stock material is to be worked upon and requires application of forces normal to the surface of the sheet, such forces may only be attained readily at points immediately adjacent to the edges of the sheets. This is because those foregoing clamps have short jaw lengths transverse to the force axis. While it is possible to increase the jaw size, this adds substantially to the weight and cost, and limits the application of the clamp to progressively larger objects. Between weight, cost and applicability to only larger work objects, the flexibility that was the benefit of these types of clamps is completely lost. 
     In order to provide access along the interior of larger planar surfaces, several clamps are available that are configured to cooperatively engage with bar clamps, and then apply forces transverse to the longitudinal bar axis. Such clamps are available, for exemplary purposes, from Bessey and referred to as edge clamps. Other clamps sold under the Bessey name include “Pony” veneer press screws, which wrap about a pipe and apply forces transverse thereto. Yet another type of veneer clamp is referenced as the “Jorgensen” press screw. The teachings of each of these clamps are hereby incorporated herein by reference. However, as is known to those in the art, these clamps are specialty clamps having very specific utility. For example, the “Pony” veneer press screws sold by Bessey are applicable only to particular diameters of black pipe, and are incompatible with other types of supports. Similarly, the “Jorgensen” press screws require a hole in a support through which the screw may pass and be anchored to. Consequently, there is not an opportunity for unlimited adjustment, nor for alternative or diverse application with either of these commercially available clamping devices. Their application and adjustment range are both undesirably limited. 
     A number of patents also illustrate exemplary clamps, similar to the Bessey clamps referred to herein above. The contents of each of these are incorporated herein by reference for the teachings that are found therein. These patents include U.S. Pat. No. 2,773,303, to Tirone; U.S. Pat. No. 2,991,669 to Stock; U.S. Pat. No. 2,816,586 to Koberle; and U.S. Pat. No. 1,201,888 to Steuber. These patents also suffer from the above described drawbacks. 
     SUMMARY OF THE INVENTION 
     In a first manifestation, the invention is a clamp having only three jaws, each with a work engaging surface, and an actuator. The second jaw work engaging surface faces the first jaw. The third jaw, which is substantially fixed in location relative to the second jaw, has a work engaging surface generally opposed to the&amp; first jaw work engaging surface. The actuator is coupled to and actuates the first jaw along a travel path. 
     In a second manifestation, the invention is a combination stand, carrier mounted upon the stand and clamp assembly slidably supported upon the carrier. Means are provided to hold the carrier in a desired position relative to the stand. The clamp assembly consists of only three jaws and a locking mechanism. A first one of the three jaws attaches to an actuating assembly that can be driven with force along a linear path. A work engaging surface faces generally in a first direction along that linear path. A second one of the three jaws attaches at a substantially fixed location along the linear path and has a work engaging surface facing generally opposed to the first jaw work engaging surface. The third jaw attaches at a second substantially fixed location along the linear path and is separated from the second jaw location by the first jaw. The third jaw also has a work engaging surface facing generally opposed to the first jaw work engaging surface. A means is provided for preventing relative motion between clamp and surface of the carrier. 
     In a third manifestation, the invention is a workpiece and associated support. The workpiece has a first major surface that is spanned by the support. A clamp has a first channel and a second channel nested in and movable relative to the first channel. The clamp second channel rigidly engages the support and the clamp first channel rigidly engages the workpiece. 
     In a fourth manifestation, the invention is a clamp. According to this manifestation, the clamp has a first u-shaped strap having a coupling and at least one jaw work engaging surface thereon. A second u-shaped strap is nested within the first u-shaped strap and has a coupling and at least one jaw work engaging surface. A means is provided for moving the first u-shaped strap relative to the second u-shaped strap. 
     OBJECTS OF THE INVENTION 
     Exemplary embodiments of the present invention solve inadequacies of the prior art by providing a plurality of jaws, including in a preferred embodiment at least one jaw nested within an exterior pair of jaws, for alternatively applying a separating force or a compressive force. A preferred configuration is illustrated which readily accommodates a wide variety of available supports that may be used for engagement, in combination with the present invention, to achieve anchoring in previously inaccessible or uneconomical locations. 
     A first object of the invention is to provide a small and easy to handle clamping attachment that may be used with existing common clamping structures to apply forces normal to and anywhere across a large planar surface. A second object of the invention is to provide this clamp for relatively low cost by avoiding the use or incorporation of difficult-to-manufacture parts. Another object of the present invention is to enable this clamp to be used either as a means for applying normal forces, or, alternatively, as a standard c-clamp. Such alternative use reduces required storage space and reduces the cost per use of the present clamp. A further object of the invention is to fabricate such a clamp that with only a minor additional component may be used for either wood contact or for metal welding exposure. Yet another object of the invention is the reduction of clearance required between a support and work piece within which the clamp may be effective. Yet a further object of the invention is the flexibility of not only clamping across major surfaces spanned by supports, but also being able to cooperatively apply edge forces or other forces transverse to a clamp, and in association with such diverse clamp types as bar, pipe, “c”, band and other clamps known in the prior art or even in association with the present clamp. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, advantages, and novel features of the present invention can be understood and appreciated by reference to the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which: 
     FIG. 1 illustrates a preferred embodiment multi-clamp designed in accord with the teachings of the present invention from a side plan view. 
     FIG. 2 illustrates the preferred embodiment multi-clamp of FIG. 1 from a top plan view. 
     FIG. 3 illustrates the preferred embodiment multi-clamp of FIG. 1 in further preferred combination with a fixture and a work surface. 
     FIG. 4 illustrates a first alternative embodiment multi-clamp designed in accord with the teachings of the present invention from a side plan view. 
     FIG. 5 illustrates a second alternative embodiment multi-clamp designed in accord with the teachings of the present invention from a side plan view. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Manifested in the preferred and alternative embodiments, the present invention provides in a single clamp the capability of applying a compressive force between two jaws directed along a single axis, as found in a prior art c-clamp. The present invention simultaneously provides in this same single clamp the ability to apply normal forces to a large sheet or planar work surface or even an edge surface through interaction with fixtures or other clamping devices, such as is found in the various veneer and edge clamps incorporated herein above by reference. 
     For the purposes of this disclosure, a jaw is herein defined as a clamp surface that applies force to a workpiece and the immediate mechanical structure upon which that surface is formed. The work engaging surface of a jaw may be planar, curved, angled, sharp, patterned, or textured. Two jaws may be constructed upon one support structure, and can be distinguished by a region of non-contact and a reaction force vector of different direction with a workpiece. A work engaging surface of a jaw is defined as that portion of the jaw that is configured to operatively contact a workpiece. There may be one or a plurality of points of contact between a work engaging surface and a workpiece. The forces applied to hold or position the workpiece may be either compressive in the case of an outside clamp, or expansive in the case of an inside clamp. 
     In accord with preferred embodiment multi-clamp  10  illustrated in FIGS. 1-3, two generally u-shaped members  20 ,  30  are nested together for relative movement there between. In preferred embodiment  10 , these u-shaped members  20 ,  30  do not need any rigid interconnection, and instead are free to move relative to one another, only limited by the movement permitted by the combination of knob  45 , threaded rod  40  and the opening in arm  23  through which threaded rod  40  passes. 
     Materials are not critical to the performance of the present invention, and these components are contemplated to be manufactured from any suitable material that is able to provide adequate strength to generate and withstand anticipated clamping forces. Nevertheless, in the most preferred embodiment multi-clamp  10 , u-shaped members  20 , 30  are fabricated from cold rolled steel and then subsequently zinc plated. The particular use of steel permits unshaped members  20 ,  30  to be fabricated in a very high volume, relatively low-cost punching operation from readily available steel. The resultant product has substantial strength, durability and corrosion resistance. Where desired, the u-shaped members  20 ,  30  may be fabricated from other processes or have other coatings applied thereto as are known in the art of metal fabrication. Common coatings such as powder coatings, various paints and lacquers, and dip coatings such as from vinyl are all contemplated herein, as are the myriad of other known materials and methods. 
     While dimensions are similarly not critical to the performance of the invention, from FIG. 2 in preferred embodiment multi-clamp  10  it is evident that u-shaped members  20 ,  30  are fabricated from steel having the same width. This is preferred since then fabrication of both members  20  and  30  from the same stock is possible, in turn increasing the volume of a single size used and lowering the total overall cost. Nevertheless, this is not essential and different sizes, thicknesses and even compositions of stock material may be used in the fabrication of these two members. 
     As is best evident in FIG. 1, one or more of the jaws may be curved, to help prevent a workpiece from slipping out of multi-clamp  10  when clamping forces are applied. This is illustrated by jaws  24  and  36 , which are both angled somewhat relative to the surrounding metal from u-shaped members  20 ,  30 . In an alternative, the entire arm extending normal to threaded rod  40  may be angled acutely with respect to the anticipated force. In such a case, any deformation would still keep the angle of contact with a square work piece at an angle adequate to pull the workpiece into multi-clamp  10  rather than push the workpiece out of engagement. As aforementioned, special coatings may be applied, or sleeves slipped around work surfaces or jaws, as desired. The use of such sleeves will permit a zinc plated clamp that would be suitable for metal work to be adapted to wood use through the provision of a polymer sleeve. 
     Operation of multi-clamp  10  will be best understood from FIG. 3, which illustrates preferred multi-clamp  10  in combination with a pipe  50  and work surface  60 . In the most preferred combination, and recognizing that the invention is not solely limited thereto but instead acquires additional significance therewith, work surface  60  is a large, planar surface, such as may be associated with sheets of lumber, particle board, chip board, plywood, laminates, and so forth. As aforementioned, the application of forces normal to the major surface of work surface  60 , which is the large planar surface in contact with jaw  26  in FIG. 3, is very difficult or impossible using prior art techniques. However, preferred multi-clamp  10  enables application of such force through a very simple and rapid process. In accord with the invention, internal u-shaped member  30 , which is in the general shape of a channel, is slipped about pipe  50 . It should be apparent that the shape of pipe  50  is not critical, so long as there is sufficient clearance to allow pipe  50  to be supported in contact with u-shaped member  30 . If not already positioned so, knob  45  may be rotated counterclockwise, or opposite to arrow  47 , to decrease the distance illustrated in FIG. 3 as gap  48 . This will allow jaw  36  to pass under pipe  50  and jaw  26  to be positioned parallel and adjacent to work piece  60 . Next, knob  45  will be rotated in the direction of arrow  47 , which will cause threaded rod  40  to pass upwards. This movement brings u-shaped member  30  closer to jaw  24  and farther from jaw  26 . In the arrangement of FIG. 3, this will lead to gap  48  increasing, until substantial force exists between pipe  50  and workpiece  60 . As long as pipe  50  is somehow anchored relative to workpiece  60 , the application of force normal to workpiece  60  may occur at any point along the longitudinal travel of pipe  50 . In a yet further preferred combination, pipe  50  will be comprised by a pipe clamp, and any point that can be spanned by such a pipe clamp may also have preferred multi-clamp  10  applied. In fact, the present invention is not limited to the application of only one multi-clamp  10 , but a plurality of similar multi-clamps may be applied. 
     As should also be apparent, the movement of knob  45  in the clockwise direction of arrow  47  may also be used to bring jaws  36  and  24  into engagement with a workpiece there between. Consequently, preferred multi-clamp  10  may be used either to apply expansive forces as shown in FIG. 3 by applying spreading forces between jaw  36  and jaw  26 , or preferred multi-clamp  10  may be used to produce compressive forces between jaws  24  and  36 . 
     Threaded rod  40  will most preferably be sufficiently long to permit jaw  36  to move into adjacent contact with jaw  26 . By permitting this contact, bar  50  may be almost immediately adjacent to work piece  60  and still be operative in association with preferred multi-clamp  10 . The minimal space required, which is only slightly more than the thickness of jaws  26  and  36 , enables the present invention to be used in many applications that would otherwise be impossible in the prior art. 
     A typical bar clamp will include a bar having an elongated shape. The bar may be integrally formed with, or attached, to another type of shape to provide decorative or functional enhancements. These other shapes might include, for exemplary purposes only and without limitation thereto, hinges, clamps, locking devices, protective end covers or shapings, edge-attached strengthening or stiffening methods, or other modifications too numerous to mention herein. Consequently, while pipe  50  has been illustrated, it will be understood that any spanning member which may be accommodated within preferred multi-clamp  10  will be satisfactory. 
     FIG. 4 illustrates a first alternative embodiment, and FIG. 5 illustrates a second alternative embodiment. The last two digits of numbering have been preserved to designate similar or like components, and consequently the descriptions will not be repeated herein except with regard to notable differences between the embodiments. With regard to first alternative multi-clamp  100  of FIG. 4, knob  145  and threaded rod  140  are rigidly connected. Consequently, when one turns, the other does also. Member  130  will most preferably be threaded or have a nut or other threaded member located about threaded rod  140 . Consequently, when knob  145  is rotated, the threads on rod  140  will drive mating threads within member  130  and thereby move member  130 . This embodiment permits member  130  to be forcefully driven either direction. Without threading member  23  where threaded rod  40  passes through, preferred multi-clamp  10  will only be driven forcefully in a single direction. 
     With respect to second alternative embodiment FIG. 5, threaded rod  240  is rigidly affixed to member  230 , but moves with respect to knob  245 . In this case, rotation of knob  245  leads to movement of both rod  240  and member  230 , thereby leading to the movement of jaw  236 . 
     While it may not be immediately apparent, the present invention is operative with only three jaws  24 ,  26  and  36 . Jaw  36  is singly operative with either jaw  24  or jaw  26 , which simplifies the construction of the invention, and also permits the illustrated bending in jaw  36  of FIG.  1 . 
     The present invention is not limited solely to one type of stock material or another, nor to one type of operation or another being performed to or with the object. Instead, it will be recognized and understood that the discussions herein are applicable to all types of materials and situations that are otherwise appropriate, as already known in the art of clamping. 
     While the foregoing details what is felt to be the preferred embodiment of the invention, no material limitations to the scope of the claimed invention are intended. Further, features and design alternatives that would be obvious to one of ordinary skill in the art are considered to be incorporated herein. The scope of the invention is set forth and particularly described in the claims hereinbelow.