WO2009135211A2

WO2009135211A2 - Grapple/tong type gripper

Info

Publication number: WO2009135211A2
Application number: PCT/US2009/042718
Authority: WO
Inventors: Benjamin M. Almeda
Original assignee: Goodcrane Corporation
Priority date: 2008-05-02
Filing date: 2009-05-04
Publication date: 2009-11-05
Also published as: WO2009135211A3

Abstract

Gripper system (20) includes complementarily shaped major jaw assemblies (102) and (104) positioned face-to-face to each other to cooperatively define an arcuate jaw capable of gripping relatively larger- sized work products (192). A minor jaw assembly (160) is pivotally mounted on at least one of the major jaw assemblies. The minor jaw assembly includes a gripping section (180) complementary to the gripping section (146) of the corresponding major jaw assembly. The minor jaw assembly is movable relative to its corresponding major jaw assembly, thereby to grip relatively small-sized work pieces (190) between the minor jaw assembly and major jaw assembly.

Description

GRAPPLE/TONG TYPE GRIPPER

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No. 61/126324, filed May 2, 2008.

BACKGROUND Field of the Invention

The present invention relates to a gripper system for a grapple- or tong-type gripping apparatus, and more particularly to a gripper system that enables a wide range of work product sizes to be gripped, lifted and moved, using a single gripper apparatus. Background

Grapple- and tong-type grippers are used in various environments, especially for loading elongated work products, such as pipes, logs, poles, and other items. The grapples or tongs are mounted on various types of cranes, including boom cranes, knuckling cranes, and overhead cranes. Such cranes can be found in many locations, such as on ships, on a mobile chassis, or at a fixed location such as in a factory or on a dock. Grapple- and tong-type grippers are also mounted on tracked or wheeled vehicles, including tractors, forklifts, skidders, etc. Typically the grapples or tongs are arranged in sets, thereby to define jaws that can open and close to grip and hold, and thereafter release the work product. Such grapples or tongs must be of a size that corresponds to the size of the work product being lifted, moved, lowered, etc. If the work product consists of small-diameter pipe, for example in a range of four to eight inches in diameter, then the grapple/tong gripper must be of an applicable size. Such grapple or tong gripper likely is not able to be used with relatively large- sized pipe, for example 24- to 36-inch diameter pipe. Thus, different equipment is needed for handling such a wide range of pipe sizes. The same is true when handling other types of work products, including logs or poles or quarry material.

SUMMARY

This summary is provided to introduce a selection of concepts in simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. A gripper system mountable on a crane, tractor, lift truck, or other apparatus or vehicle for grasping work products of a wide size range, consisting of first and second major jaw assemblies defining first and second major gripping surfaces, and an actuator for opening and closing the first and second major jaw assemblies relative to each other, so that the first and second major gripping surfaces move toward and away from each other to grasp and release work pieces. The gripper system also includes first and second thumb assemblies pivotally mounted on respective first and second major jaw assemblies, the first and second thumb assemblies defining first and second minor jaws. An actuator system moves the first minor jaw relative to the first major gripping surface to enable the grasping of work pieces between the first minor jaw and the first major gripping surface. Correspondingly, the actuator system for the thumb assemblies moves the second minor jaw relative to the second major gripping surface to enable the grasping of work pieces between the second minor jaw and the second major gripping surface.

In accordance with a further aspect of the present disclosure, the actuator system for the thumb assemblies moves the first minor jaw relative to the first major gripping surface, and moves the second minor jaw relative to the second major gripping surface to enable the gripping of work pieces between the first minor jaw and the first and second major gripping surfaces, as well as between the second minor jaw and the first and second major gripping surfaces.

The gripper system further includes a third major jaw assembly, positioned so that the second major jaw assembly is disposed between the first and third major jaw assemblies. The third major jaw assembly defines a third major gripping surface. The first actuator also opens and closes a third major jaw assembly to move in unison with the first major jaw assembly.

A third thumb assembly is pivotably mounted on the third major jaw assembly, the third thumb assembly defines a third minor jaw. The thumb assembly actuator system moves the third minor jaw relative to the third major gripping surface to enable the grasping of work pieces between the third minor jaw and the third major gripping surface.

In accordance with a further aspect of the present disclosure, a gripper system is provided for gripping work pieces of a wide span of sizes, with the gripper system including a first major tong assembly which defines the first gripping section, a second major tong assembly positioned complementary to the first major tong assembly, the second major tong assembly defining a second gripping section. The gripper system also includes a third major tong assembly positioned in an orientation corresponding to the first major tong assembly. The major tong assemblies are positioned so that the second major tong assembly is disposed relatively between the first and third major tong assemblies. A first actuator moves the first and third major tong assemblies relative to the second major tong assembly, thereby to move the gripping sections of the first and third major tong assemblies relative to the gripping section of the second major tong assembly to enable relatively large sized work pieces to be gripped between the gripping sections of the first, second and third major tong assemblies. In addition, a minor tong assembly is associated with at least one of the first, second and third major tong assemblies. A second actuator moves the minor tong assembly relative to its corresponding major tong assembly to enable relatively smaller sized work pieces to be gripped between the minor tong assembly and the gripping section of the corresponding major tong assembly.

In accordance with a further aspect of the present disclosure, a minor tong assembly is mounted on each of the major tong assemblies. The second actuator moves each minor tong assembly relative to the corresponding major tong assembly to enable the gripping of a work piece between each minor tong assembly and one or more of the corresponding major tong assemblies.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a side elevational view of a knuckle crane employing a gripper assembly of the present disclosure;

FIGURE 2 is an elevational view of a gripper assembly of the present disclosure;

FIGURE 3 is an elevational view of the gripper assembly of FIGURE 2, shown at 90° from FIGURE 2, shown gripping a relatively large diameter pipe;

FIGURE 4 is a partial cross-sectional view of FIGURE 3 taken along lines 4-4 thereof;

FIGURE 5 is a partial cross-sectional view of FIGURE 3, taken along lines section 5-5 thereof;

FIGURE 6 is a side elevational view of an outer jaw assembly; FIGURE 7 is a side elevational view of a center jaw assembly;

FIGURE 8 is a side elevational view of an outer jaw assembly opposite the jaw assembly of FIGURE 6;

FIGURE 9 is a side elevational view of a thumb assembly utilized with each of the outer and center jaw assemblies of FIGURES 6, 7, and 8; and

FIGURE 10 is a pictorial view of a gripper system gripping a relatively small-diameter pipe.

DETAILED DESCRIPTION

Referring initially to FIGURE 1, gripper system 20 of the present disclosure is illustrated as mounted on the distal end of a knuckle crane 22, which in turn is mountable on a vessel, ship, or other location offshore or on shore. Moreover, although the gripper system 20 is shown as being used in conjunction with a knuckle crane 22, the gripper system can be used with other types of cranes or in numerous other applications, for instance, in conjunction with a loader vehicle, a boom crane, an overhead crane in a warehouse, factory, or other work setting, essentially anywhere where it is necessary to lift, move, load, etc., work products of a wide range of sizes, including a wide range of widths or diameters.

Referring to FIGURE 1, knuckle crane 22 includes a base structure 24 in the form of an upright pedestal 28 that is receivable within a corresponding structure on a ship or other location. The pedestal allows the crane to be rotated about the pedestal by a rotational drive system that can be of standard construction.

A cab 30 is mounted on a platform 32 at the upper end of the pedestal 28. As is typical, the cab 30 is designed to house the crane operator in a weather-tight environment. The crane further includes a lower arm 34 having a proximal end pivotally mounted on spaced-apart mounting ears 36 extending upwardly from base platform 32. A cross pin 38 is carried by the mounting ears and engages through a cross hole formed in the lower end portion of arm 34. The lower arm 34 can be raised and lowered by actuation of linear actuators that may be in the form of hydraulic cylinders 40 having their proximal ends pinned to base platform 32 and their distal ends pinned to an intermediate location along the length of the lower arm 34.

The crane 22 also includes an upper arm 50 having a proximal end portion pinned to the distal end portion of the lower arm 34 by a pin arrangement 52. The upper arm may be of telescoping or non-telescoping configuration. The upper arm 50 is pivotable about pin 52 relative to the lower arm 34 by linear actuators that may be in the form of hydraulic cylinders 54, with the proximal ends of the cylinders pivotally pinned to an intermediate location along the lower arm 50 at pivot location 56, and with the distal rod end portions of the cylinders 54 pinned to an intermediate location 58 along the upper arm 50. Operation of the linear actuators/hydraulic cylinders 40 and 54 enable the crane 22 to be raised and lowered as well as extended and retracted in a typical manner.

The gripper system 20 is coupled to a hydraulic rotational motor 60 which in turn depends downwardly from a mounting bracket arrangement 62, one end of which is pivotally pinned at 64 to a distal end extension 66 extending a relatively short distance from the distal end of the upper arm 50. The rotary motor 60 enables the gripping system 20 to be rotated about a central axis 68, thereby to position the gripping system 20 at a desired angle or orientation about the axis 68. A rotatable shaft 70 extends downwardly from the rotational motor 60 to engage within a hub assembly 72 mounted centrally on a frame 74 of the gripper system 20. As shown in FIGURE 1, triangularly shaped gusset reinforcing plates 76 extend between the outer diameter of the hub assembly 72 and the upper surface of the frame 74 to reinforce the mounting of the hub assembly on the frame 74.

It is to be understood that the present disclosure also contemplates the ability to pivot gripper system 20 relative to upper arm 50 about pin 64, thereby to tilt the gripper system to a desired angle about the horizontal as shown in FIGURE 1. Also, it is contemplated that the gripper system 20 may be pivoted relative to the upper arm 50 about an axis perpendicularly to pin 64. Such pivoting of the gripper system 20 relative to the upper arm 50 can be accomplished by use of hydraulic or electrical rotational motors similar to motor 60, or by the use of linear actuators, not shown, acting between mounting bracket 62 and extension 66, or between the mounting bracket 62 and the distal end portion of the upper arm 50.

Referring to the construction of the gripper system 20, two gripper assemblies 100 are illustrated in FIGURE 1, one mounted at each end of the frame 74. Such gripper assemblies are illustrated in FIGURES 2 and 3, with details thereof also shown in FIGURES 4-10. In basic form, each gripper assembly 100 consists of a pair of outer major jaw or tong or grapple assemblies 102 and 104, and a central major jaw/tong/grapple assembly 106 positioned between the outer jaw assemblies. The terms "jaw assembly," "tong assembly" and "grapple assembly" are used synonymously in the present disclosure. The two outer jaw assemblies 102 and 104 are pivotally mounted on a cross shaft 110 that is journaled at the lower ends of four spaced apart mounting walls 112a, 112b, 112c and 112d that depend downwardly from a top plate 114 of gripper assembly mounting box 116, see FIGURES 2, 3, and 5. As shown in FIGURE 2, mounting wall 112d extends upwardly above the elevation of the top plate 114 and is used to secure the box 116 to the end of frame 74. The box 116 is mounted to the frame 74 via the mounting wall 112d using bolts or other appropriate means extending through clearance openings in wall 112d to engage with threaded openings in the frame or other means. Appropriate bearings or bushings are utilized between the cross shaft 110 and the mounting walls 112a, 112b, 112c, and 112d for anti-friction rotation of the cross shaft 110. For reinforcement purposes, triangular gusset plates 118 extend between the upper side of the top plate 114 and the adjacent face of end wall 112d.

Referring specifically to FIGURES 3 and 5, a pinion gear 120 is mounted centrally on cross shaft 110 between mounting plates 112b and 112c. Pinion gear 120 meshes with a rack 122 that is mounted on the lower end of a plunger shaft 124 depending downwardly and outwardly from a linear actuator or rack cylinder 126. Thus, by raising and lowering the rack 122, the pinion gear 120 is rotated about the central axis 130 of shaft 110, which in turn rotates the outer jaw assemblies 102 and 104 about the same axis 130, as described more fully below.

As shown in FIGURES 2, 3, 5, 6, and 8, the outer jaw/tong/grapple assemblies 102 and 104 are constructed virtually identically to each other; thus, the following description applies to both assemblies. Each assembly 102 and 104 includes a curved major jaw/tong/grapple 140 consisting of spaced-apart side plates 142 and 144 that are mounted on the cross shaft 110 to rotate therewith. As shown in FIGURE 3, the side plates 142 depend downwardly from shaft 110 and are formed in a generally curved shape to define an arcuate, inwardly concave gripping section 146. At cross shaft 110, the side plates 142 and 144 are rigidly fixed to a hub section 148 that is sized to closely receive the cross shaft 110. Splines, key ways, or other means can be used to anti-rotationally fix the hub section 148 to the cross shaft 110.

At the distal or lower end portions of the side plates 142 and 144, a tip section 150 is sandwiched between the side plates to extend beyond the end of the side plates and taper to a tip end portion 152. As will be appreciated, the tip end portion maintains the desired separation and parallelism between the side plates 142 and 144. A back cover plate 154 extends along the outerward edge portions of the side plates 142 to span between the side plates. The cover plate 154 is curved to correspond to the curvature of the outer edge portions of the side plates 142 and 144. In addition, wear pads 156 extend along the inside edge portions of the side plates 142 and 144 to define gripping or grasping surfaces. The wear pads 156 are arcuate and shaped to correspond to the shape of the gripping sections 146 of the side plates. The wear pads can be removable, thereby to be replaced as needed. The wear pads are held in place by a series of threaded hardware members 158 extending through counter-sunk through holes formed in the wear pads to engage threaded blind holes forming in side plates 142 and 144. It will be appreciated that the side plates 142 and 144 can be reinforced by using additional stiffening plates or additional separator plates positioned between the side plates, etc., thereby to increase the structural integrity of the jaw assemblies as needed.

Referring specifically to FIGURES 2, 3, 5, 9, and 10, the outer jaw/tong/grapple assemblies 102 and 104 also include a thumb or minor tong assembly 160 that constitutes a minor jaw assembly. The thumb assembly 160 is pivotally mounted by pin 162 to the outer jaw assembly between the side plates 142 and 144 to enable the thumb to pivot about axis 164 between a retracted position shown in FIGURE 3 and an extended or in-use position shown in FIGURE 10. When the thumb assembly 160 is in a retracted position, it is within the envelope defined by the side plates 142 and 144, see FIGURE 3. The thumb assembly 160 is pivotable about axis 164 by a linear actuator 170 pivotally mounted to upper end portions of the side plates 142 and 144 by a cross pin 172. The distal or lower end portion of the linear actuator includes a clevis 173 that is pinned to a mounting ear 174 extending transversely outwardly from the upper or shank portion 175 of thumb assembly 160 by pin 176. The linear actuator 170 pivots the thumb assembly 160 about axis 164. The thumb assembly 160 includes an arcuately shaped gripping section 180. A wear pad 182 extends along the gripping section 180, and may be designed to be removable, thus replaceable in a manner similar to wear pads 156.

The thumb assembly 160 is shown being in a retracted position in FIGURE 3. In FIGURE 10, the thumb is shown as being extended so as to grip a smaller diameter pipe 190 between the gripping section 180 of the thumb and the gripping section 146 of an outer jaw assembly, as well as the gripping section 246 of the central jaw assembly 106, described below. As noted above, the gripping system 20 also includes a central major jaw assembly 106, as shown in FIGURES 2, 3, and 4. The central jaw assembly 106 is mounted on frame 74 to be in face-to-face relationship with the outer jaw assemblies 102 and 104. To this end, the central jaw assembly 106 is constructed similarly to outer jaw assemblies 102 and 104; thus, the description of the central jaw assembly 106 will be abbreviated, with the understanding that for the most part, the construction and function of the central jaw assembly 106 is essentially the same as that for outer jaw assemblies 102 and 104. In this regard, the components of central jaw assembly 106 that correspond to outer jaw assemblies 102 and 104 are identified by the same part numbers, but in a 200 series rather than in the 100 series of part numbers used for the outer jaw assemblies.

With respect to the center jaw assembly 106, it likewise is composed of a pair of side plates 242 and 244 that are journaled on a cross shaft 210, with the outer ends of the cross shaft journaled on the lower end portions of mounting walls 112b and 112c, which are also used for mounting the outer jaw assemblies 102 and 104, described above. Roller bearings or other types of antifriction means 211 are interposed between the shaft 110 and the mounting walls 112b and 112c. The pinion gear 220 is positioned over hole 248 which in turn is disposed over the central portion of shaft 210 to cause the shaft to rotate with the pinion gear. As with pinion gear 120, pinion gear 220 meshes with rack 122, but on the opposite side of the rack as the location of pinion gear 120. As such, central jaw assembly 106 moves in coordination with outer jaw assemblies 102 and 104 with the extension and retraction of plunger shaft 124. When the outer jaw assemblies 102 and 104 and central jaw assembly 106 are pivoted towards each other far enough, the central jaw assembly 106 extends between the outer jaw assemblies.

In construction, the center jaw assembly 106 is very similar to the construction to the outer jaw assemblies 102 and 104. Also, as with the outer jaw assemblies 102 and 104, the central jaw assembly 106 includes a thumb or minor tong assembly 260 (constituting a minor jaw assembly) positioned between the side walls 242 and 244 of the central jaw assembly and pinned thereto by a cross pin 262 so as to pivot about cross axis 264, see FIGURE 3. The thumb assembly 260 may be of the same or very similar construction as thumb assembly 160. The thumb assembly 160 is pivoted about axis 264 by a linear actuator 270 in the same manner in which the thumb assemblies 160 are operated through linear actuator 170. As such, the thumb assembly 260 is capable of holding smaller diameter work products between its gripping section 280 and the corresponding gripping section 246 of the central jaw assembly 106, and the gripping sections 146 of the outer jaw assemblies 102 and 104, see FIGURE 10.

Briefly, in operation of gripper assembly 20, the major or outer jaw assemblies 102 and 104 cooperate with major central jaw assembly 106 to grasp and support therebetween relatively large sized work products such as pipe 192, shown in FIGURE 3. Such pipe may be, for example, at least two to three feet or meters in diameter. Work products can have the diameter at least as large as the diameter defined by the curvature of the arcuate gripping section 146 and/or wear pads 156 utilized in conjunction with the outer jaw assemblies 102 and 104. As noted above, the jaw assemblies 102 and 104 are moved relative to jaw assembly 106 by actuating of linear actuator 126.

It will be appreciated that it is difficult for the outer jaw assemblies 102, 104, and 106 to grasp and securely hold smaller sized diameter work pieces. However, smaller sized diameter work pieces, for example, pipes as small as two inches diameter, can be securely held through the use of thumb/minor tong assemblies 160 in conjunction with the outer jaw assemblies 102 and 104, as well as the thumb/minor tong assemblies 260 in conjunction with corresponding central jaw/tong assembly 106. As noted above, the thumbs 160 and 260 are operated/actuated by linear actuators 170 and 270 to move between retracted positions shown in FIGURE 3, and an "in-use" position shown in FIGURE 10. In FIGURE 10, a smaller diameter work piece is cradled between outer and central jaw assemblies 102, 104, and 106, and with thumbs 160 and 260 holding the work piece against the jaw assemblies 102, 104 and 106. As will be appreciated, in this manner a smaller diameter work piece can be securely held by use of the gripping system of the present disclosure.

Referring to FIGURE 1, the gripping system 20 may include gripper assemblies 100 positioned at opposite ends of the frame 74. In this manner, relatively long work pieces, of large or smaller size diameter, can be conveniently grasped, lifted, moved, and placed in a desired location by the use of the gripping system 20 of the present disclosure.

It is to be understood that the foregoing description is meant only to be illustrative of the present invention. Changes, alterations, and substitutions can be made to the above-described disclosure. For example, gripping system 20 can be mounted on numerous machines, apparatus, vehicles, including mobile cranes, fixed cranes, overhead cranes, loaders, lift trucks, tractors, trucks, crawlers, yarders, etc. Also, rather than gripper assembly 100 being composed of two outer jaw assemblies and a central jaw assembly, different combinations of jaw assemblies may be utilized, including gripper assemblies composed of two jaw assemblies, four jaw assemblies, etc. Moreover, the jaw assemblies may be actuated in a manner other than is described above. For example, each jaw assembly might include a linear actuator to move the jaw assembly about frame 74. Also, linear actuators 170 and 270 may be replaced with other actuation systems, including rotary motors, rack and pinion systems, etc. Further, the thumb assemblies could be configured and operated to hold smaller work pieces against only their corresponding major outer jaw or inner jaw assemblies respectively, rather than against both the major outer and inner jaw assemblies.

Claims

CLAIMSThe embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A gripper system mountable on an apparatus for grasping work products of a wide size range, comprising:

(a) a first major jaw assembly defining a first major gripping surface;

(b) a second major jaw assembly defining a second major gripping surface;

(c) a first actuator for opening and closing the first and second major jaw assemblies relative to each other so that the first and second major gripping surfaces move towards and away from each other;

(d) a first thumb assembly pivotally mounted on the first major jaw assembly, said first thumb assembly defining a first minor jaw;

(e) a second thumb assembly pivotally mounted on the second major jaw assembly, said second thumb assembly defining a second minor jaw; and

(f) a thumb assembly actuator system for:

(i) moving the first minor jaw relative to the first major gripping surface to enable the grasping of work pieces between the first minor jaw and the first major gripping surface; and

(ii) moving the second minor jaw relative to the second major gripping surface to enable the grasping of work pieces between the second minor jaw and the second major gripping surface.

2. The gripper system according to Claim 1, wherein said first major jaw assembly comprises spaced-apart jaw plates and said first thumb assembly is positioned between the spaced-apart jaw plates.

3. The gripper system according to Claim 1, wherein said second major jaw assembly comprises spaced-apart jaw plates and wherein the second thumb assembly is positioned between the spaced-apart jaw plates.

4. The gripper system according to Claim 1, wherein the major gripping surfaces of the first and second major jaw assemblies are generally arcuate in shape and nominally oriented so that the first major jaw assembly presents a concave first major gripping surface towards the second major jaw assembly and so that the second major jaw assembly presents a second concave major gripping surface toward the first major jaw assembly.

5. The gripper system according to Claim 1, wherein the first thumb assembly defines a first minor jaw complementary to the first major jaw assembly, and wherein said second thumb assembly defines a second minor jaw complementary to the second major jaw assembly.

6. The gripper system according to Claim 1, wherein the thumb assembly actuator system moves the first minor jaw relative to the first major gripping surface, enabling the grasping of work pieces between the first minor jaw and the first and second major gripping surfaces.

7. The gripping system according to Claim 1, wherein the thumb assembly actuator system moves the second minor jaw relative to the second major gripping surface to enable the grasping of work pieces between the second minor jaw and the first and second major gripping surfaces.

8. The gripper system according to Claim 1, further comprising: a third major jaw assembly, said third major jaw positioned so that the second major jaw assembly is disposed between the first and third major jaw assemblies, and defining a third major gripping surface; and said first actuator also opening and closing said third major jaw assembly to move in unison with said first major jaw assembly.

9. The gripper system according to Claim 8, further comprising a third thumb assembly pivotally mounted on the third major jaw assembly, said third thumb assembly defining a third minor jaw.

10. The gripper system according to Claim 9, wherein said third major jaw assembly comprising spaced-apart jaw plates and said third thumb assembly is positioned between said spaced-apart jaw plates.

11. A gripper system for gripping work pieces of a wide span of sizes, comprising:

(a) a first major tong assembly, said tong assembly defining a first gripping section;

(b) a second major tong assembly positioned complementary to the first major tong assembly, said second major tong assembly defining a second gripping section;

(c) a third major tong assembly positioned in an orientation corresponding to the first major tong assembly, said second major tong assembly positioned relatively between the first and third major tong assemblies, said third major tong assembly defining a third gripping section;

(d) a first actuator for moving the first and third major tong assemblies relative to the second tong assembly, whereby to move the gripping sections of the first and third major tong assemblies relative to the gripping section of the second major tong assembly to enable relatively larger work pieces to be gripped between the gripping sections of the first, second, and third major tong assemblies;

(e) a minor tong assembly associated with at least one of the first, second, and third major tong assemblies; and

(f) a second actuator to move the minor tong assembly relative to its corresponding major tong assembly to enable relatively smaller work pieces to be gripped between the minor tong assembly and the gripping section of the corresponding major tong assembly.

12. The gripper system according to Claim 11, wherein said first minor tong assembly is pivotally mounted on a corresponding major tong assembly.

13. The gripper system according to Claim 12, wherein the major tong assembly corresponding to the minor tong assembly comprising spaced-apart side plates defining the major tong assembly; and said minor tong assembly positioned between said side plates.

14. The gripper system according to Claim 11, further comprising: a minor tong assembly corresponding to each major tong assembly; and said second actuator moving each minor tong assembly relative to the corresponding major tong assembly to enable the gripping of a work piece between each minor tong assembly and the corresponding major tong assembly.

15. The gripper system according to Claim 11, wherein the gripping section of each major tong assembly is arcuate in shape, whereby the gripping sections of the first and third major tong assemblies presenting a concave gripping section towards the gripping section of the second major tong assembly, and correspondingly the arcuate gripping section of the second major tong assembly presenting a concave gripping section towards the gripping sections of the first and third major tong assemblies.

16. The gripper system according to Claim 15, wherein said minor tong assembly defining a gripping section shaped to be complementary to the shape of the gripping section of the associated major tong assembly.

17. The gripper system according to Claim 11, wherein the first actuator pivots the first and third major tong assemblies in unison relative to the second major tong assembly.

18. The gripper system according to Claim 11, wherein the first actuator pivots the first, second, and third major tong assemblies in unison.

19. The gripper system according to Claim 11, wherein the second actuator system moves the minor tong assembly relative to its corresponding major tong assembly to enable relatively smaller work pieces to be gripped between the minor tong assembly and the gripping sections of the first, second and third major tong assemblies.