Patent Grant
7568372
The invention generally pertains to rescue tools for emergency operations, and more specifically to a hydraulic tool that is designed to sever material, pry apart structural elements and crush material to rescue a person that is trapped in a damaged vehicle.
Previously, many types of rescue tools have been used to provide an effective means to pry or cut open damaged vehicles at the scene of an accident. Further, other machine tools have been developed with similar operational characteristics.
A search of the prior art did not disclose any patents or industry literature that read directly on the claims of the instant invention. However, the following U.S. patents are considered related:
Hurst in U.S. Pat. No. 3,819,153 teaches a portable rescue tool using fluid actuated force that is movable along the longitudinal axis of the base for positioning the arms to move the outer ends toward and way from each other to close and open.
U.S. Pat. No. 4,333,330 issued to Porter is for a spreader tool that has opposed force arms which are separated and pivoted while mounted on a base member. When separated and pivoted, the arms achieve annular movement in an opposite direction in response to axial movement of a driven piston of an associated jack. The inner edges of the arms rest upon rollers mounted on the forward end of the piston. A curve of the inner edge of the arms form an angle at which a constant axial force of the piston is applied to the arm by the roller such that the force is always constant.
Amoroso in U.S. Pat. No. 4,392,263 teaches a rescue tool including a body with a cylinder and an outward-extending piston. Jaw members are connected to the body with links and include outer prying portions, inner cutting portions and intermediate shearing portions. The tool may be powered by a bi-directional motor or directly from a wrecker motor vehicle system.
U.S. Pat. No. 4,734,983 issued to Brick teaches a cutting tool that is effective for cutting through sheet metal when extricating accident victims. The tool has one curved movable blade and one stationary blade. The stationary blade is formed on an anvil that is anchored within the frame of the tool and locked within the frame with a dowel.
U.S. Pat. No. 5,301,533 of Jackson discloses a machine tool that relates to manufacturing operations for gripping, clamping, piercing and hemming workpieces. Two pairs of arms are arranged in an opposed, inverted relationship with respect to each other and are pivotally connected at one end to the drive. Each arm has a cam formed therein. The cams in each of the pairs of arms are identically constructed in opposed inverted relationship. Cam followers, which are mounted on the linear drive member, engage the cams during movement to pivot the arms between the open and closed position. Each cam has an arcuate shape at an obtuse angle with respect to a pivot pin that connects each of the pairs of arms the drive.
U.S. Pat. No. 5,544,862 of Hickerson is for a spreading tool that is actuated by an electric motor. Torque at any position is achieved with selectable spreading or cutting motions using a rotary multiple stage speed-reducing gearbox, which is driven by a motor running on a 12 volt DC power supply.
Painter et al in U.S. Pat. No. 5,622,353 discloses a rescue tool having a pair of spreader arms with a pivot point therebetween. A pair of links attached to the arms are reciprocally moveable between retracted and extended positions along an axis of movement. A third pivotal coupling couples the spreader arm pivot point to the housing.
U.S. Pat. No. 5,956,992 issued to Patton, the instant inventor, is for a rescue tool consisting of a first arm that functions in combination with an interlocking second arm, which operates with a drive yoke. Another yoke includes a pair of cam pins that traverse a cam slot in each arm and a drive rod is connected to the drive yoke.
Patton's own U.S. Pat. No. 6,244,568 teaches a rescue spreading tool that provides a spreading, crushing or cutting motion. A stationary yoke is attached to a cylinder and a pair of spreader arms are attached to the cylinder and are free to rotate in opposed directions. A pusher cam yoke is formed integrally with the cylinder ram and engages the arms, thereby pushing them apart when the ram is extended. A pair of toggle links attached to the yoke continue to push the arms apart, thus creating a secondary thrust.
U.S. Pat. No. 7,107,812 also of Patton is for a hydraulic rescue tool utilizing a hydraulic cylinder with a yoke attached, with a handle for manipulating the tool. Rotation of the cylinder yoke prevents injury if the tool binds. Pivotal links connect the implement unit with quick release pins, thus making the implement unit easily removable. Two embodiments of the implement unit are taught, with a cutter unit for severing material and a spreader unit for prying apart structural elements when a vehicle is deformed to rescue a trapped victim.
For background purposes and as indicative of the art to which the invention is related, reference may be made to the remaining patents located in the patent search:
The problem with hydraulic rescue tools in the past has been insufficient power to accomplish the task at hand and excessive weight for emergency personnel to handle the tool efficiently. At the present time fuel economies and stricter government regulated impact safety standards have dramatically changed the design of motor vehicles. As an example, door hinges are now stamped of chromemoly steel, heat treated forgings and even Boron laminates. Windshield posts and roof lines, as well as side impact beams, now require high strength alloys. It is anticipated that by 2010 vehicles will utilize posts and roofing made of 0.120 inch (0.30 cm) thick Boron tubes that are heat treated to 55 Rockwell hardness and welded into the vehicle's roof structure.
As any tool that opens and closes, requires tremendous forces on a cylinder structure that is included on the tool. For example, typical production rescue tools today require from 100,000 pounds to 155,000 pounds of hydraulic force. It has been found that 200,000 pounds of force is now necessary to meet 5-star vehicle crash demands, thus necessitating a cylinder of equivalent strength. Further, mechanical structures of the tools now employed for this purpose are being flexed each time the tool is required to be fully loaded, thereby causing the cylinder to be oblonged at the front in time, which creates leaks or even catastrophic failures with continued use when the higher force loads are required.
The most serious problem is that many of the rescue tools in production today simply do not have the mechanical advantage and power required to handle the rescue tasks.
Therefore, the primary object of the invention is to provide a rescue tool that has sufficient power to sever or separate a vehicle structure that has been damaged and yet is light enough to be easily handled by emergency operation personnel. To overcome the pressure requirements and to be within the weight limitations the instant invention utilizes a hydraulic cylinder that has discrete ears made of a heat treated steel alloy. The ears penetrate an enlarged portion of the cylinder and are held in place between a removable gland with fasteners. This approach overcomes the weight of conventional aluminum ears that are integrally formed with the cylinder and the strength requirement of attachment yokes and brackets that have been positioned around the cylinder in the past. The use of a separate gland that is bolted in place permits higher pressures to be utilized as there are no threads, spiral locks, snap rings or welding requirements, as are required in the prior art rescue tools.
An important object of the invention is that one single thrust apparatus, consisting of the hydraulic cylinder with links attached to the encapsulated ears on each side, may be used in concert with multiple quick disconnect implement units that are easily detachable in the field. To detach the implement unit from the thrust apparatus only three pins must be removed, with each pin tethered to accommodate its quick release and ease of replacement.
Another object of the invention is that there are provisions for safety of the operator when pressure is forced to be increased the probability that a blade or arm may break off from the tool and become a missile has been a real fear for an operator. In the past safety cables have been used to overcome this problem, however it has been found that if breakage occurs the safety cable simply causes the blade or arm to return to its original location, thus creating a boomerang like which places the operator in an even greater jeopardy. The instant invention circumvents this problem by utilizing an energy absorbing member, which is constructed of flat malleable mild steel that is welded in place on an exposed underside surface of the blade or arm. If breakage occurs the energy absorbing member bends and stretches to keep the broken part from completely flying off.
Of less importance but potentially injurious is a pinch point located between the ears or pivot points and the links, which has been eliminated by encapsulating the joint with an integral barrier at the point of movement. Another possible concern is the pinching of the rear handle against a solid object since prior art handles are usually rigid. The rear handle of the instant invention is spring-loaded to yield, within limitations, thereby reducing, if not completely eliminating the pinching effect. The front handle has likewise been improved by using a bracket that is collapsible, which moves out of the way when engaging a solid structure and yet is positioned with a detent when used in an upright position.
Additionally, pressure relief valves are provided to limit the hydraulic pressure on either side of the piston rod for pushing and pulling actions, thereby preventing over pressurization.
Still another object of the invention is also related to the collapsible handle advantage as the handle may pivot down on an enlarged portion of the cylinder body when working in tight areas. The size of the thrust apparatus limits the ability to reach damaged areas in the vehicle structure.
Another advantage of the tool is the ability to fold down the front handle so that storage is easier, as storage areas in emergency vehicles are usually limited.
Yet another object of the invention is that the links have a hollowed out web in the sides and in the upper surface with finger grooves, thereby providing another gripping area to lift the tool during handling and operation. Another improvement is that force level markings are provided on the cutter and spreader arms, indicating to the operator the capabilities of the tool relative to the distance from the pivot point.
A further object of the invention is the ease of maintenance as the invention's sealing gland may be removed as a unit by detaching only two bolts and nuts protecting the seals on the piston or gland surface as there are no sharp threads or snap ring grooves that may be hit or scratch the lip of the seal. Further, the gland slides over the piston rod and since the sides are tapered, removal and replacement are easily accomplished.
A final object of the invention provides illumination of the three pins that allow removal and replacement of the quick disconnect implement unit. This convenient feature is accomplished by using a light emitting diode (LED) having an integral battery that is located within a knurled pin cap. Optionally, an additional LED can be added to the yoke which may become separated from the jaws, blades or arms of a structure separating apparatus during storage. Further, the pins utilized as link pins incorporate a retractable spring-loaded tether, which allows the link pin tether to be stored in tension in a hollow side of the link and when required is retracted under compression of the spring and returns to its at rest position when released permitting the link pin tether to be concealed within the linkage when not in use. The yoke pin is simply tethered to the yoke with a cable. All of the pins incorporate an adjustable spring-loaded detent which permits changing the amount of force required to remove the pin from the device.
These and other objects and advantages of the present invention will become apparent from the subsequent detailed description of the preferred embodiment and the appended claims taken in conjunction with the accompanying drawings.
The best mode for carrying out the invention of the hydraulic rescue tool 10 is presented in terms of two separate units: a unitary thrust apparatus 20 producing the energy to operate the tool and a quick disconnect implement unit 22 which includes a vehicle structural separating apparatus. The thrust apparatus 20 is exactly the same for all of the embodiments and is shown in
The same thrust apparatus 20 is used in conjunction with all of the various implement units 22 and is comprised of an interlocking unitized hydraulic cylinder body 24 having a hollow enlarged end 26 containing a mating pair of opposed slots 28 in each side of the enlarged end 26. The hydraulic cylinder body 24 is preferably made of a high grade aluminum alloy or other material such as titanium, metal matrix or carbon fiber, with the enlarged end 26 hollowed in a rectangular shape.
A piston rod 30 is disposed within the hydraulic cylinder body 24, with the rod 30 incorporating a sealing member 32 on the end enclosed in the hydraulic cylinder body 24. The piston rod 30 slideably extends from and retracts within the hydraulic cylinder body 24. The piston rod 30 is preferably constructed of steel and has a yoke attaching bore 34 in an end opposite the sealing member 32.
A pair interlocking ears 36 having a T-shape are disposed within the hydraulic cylinder body 24 hollow enlarged end 26, with a leg of the T protruding from each elongated slot 28 on the sides of the cylinder's enlarged end. The interlocking ears 36 are made of high tensile steel, stainless steel, titanium, fiber metal matrix, or high-strength light-weight carbon fiber, with heat treated steel preferred. The ears 36 are configured to interface with an inner surface of the hydraulic cylinder body 24 hollow enlarged end 26, with the ears 36 extending from the slots 28.
A gland 38 is interfaced between the interlocking ears 36 and locked in place with at least two fasteners, such as conventional pins and rivets, with gland attaching bolts 40 with nuts 42 preferred which penetrate completely through the gland 38 and both ears 36 onto the outer surfaces of the cylinder enlarged end 26. The gland 38 is basically an assembly consisting of a metallic body having a rectangular shape on the exposed end and round shape on the end interfacing with the cylinder bore. A number of seals are utilized, including a piston rod seal 44 that is installed on the inner surface of the gland 38 interfacing with the piston rod 30, a gland seal 46 that is positioned on the round end of the gland 38 engaging the cylinder body 24, and a rod wiper seal 48 that is positioned on the external side of the gland 38.
The configuration of the gland 38 permits removal of the entire assembly in the field with common tools for servicing the seals when the bolts 40, nuts 42, pins or rivets are removed which have jointly interlocked the ears 36 and the gland 38 within the hollow enlarged end of the cylinder body 26.
A connecting link 50 is attached on a first end 52 to each extending interlocking ear 36 and on a second end 54 to the vehicle structure separating apparatus 90. The connecting link 50 is offset in shape and is preferably of aluminum construction formed with a clevis 56 on each end. A central portion of each side is recessed forming an I-shape, with the upper and lower outer surface having finger gripping grooves 58 and the first end 52 forming an enclosed end which prevents finger pinching during manual handling of the rescue tool 10.
The second end 54 of the connecting link 50 is configured to receive a removable link pin 60 having a first self-contained LED 62 installed within its head. The removable link pin 60 has an adjustable ball detent 64 and a retractable spring-loaded link pin tether 66 attached to its head. The link pin tether 66 is always stored in tension in the hollow side of the link 50 and is retracted under compression of the spring, thereby permitting the link pin tether 66 to be concealed within the linkage when not in use.
The link pin tether 66 that preferably consists of wire rope 68 that is attached to a extension spring 70 on one end and looped around the link pin 60 on the other end, with the spring 70 housed in semi-flexible tubing 72. When the pin 60 is removed from the link 50 the spring 70 is extended, and when replaced the wire rope 68 is pulled back into the tubing 72 by the spring 70 to an at rest position within the tubing 72.
Handles are provided for lifting and operating the rescue tool 10 including a forward fold-down handle 74 which is attached to the enlarged end 26 of the hydraulic cylinder body 24. A rearward yieldable handle 76 is attached onto an end of the hydraulic cylinder body 24 opposite the enlarged end 26, with the handles 74 and 76 made from a material consisting of a coated metal, an insulation coated metal or an electrically non-conductive substance.
Hydraulic controls are attached to the cylinder body 24 for regulating hydraulic pressure. The hydraulic controls consist of an in and out directional control lever 78 for the hydraulic thrust mechanism 20 to manually select the piston rod 30 thrust and retraction position.
A reverse thrust pressure relief valve 80 is attached through the gland 38 and a forward thrust pressure relief valve 82 is positioned through the end of the cylinder body 24 to relieve excessive hydraulic pressure for safety protection.
The hydraulic thrust apparatus 20, as described above and illustrated bracketed in
The six discrete embodiments of the quick disconnect implement unit 22 that are optionally connected to the hydraulic thrust apparatus 20 complete the hydraulic tool 10. Each embodiment requires a yoke 84 with a yoke body 86 attached to the piston rod 30 and with a tethered yoke pin 88 and a vehicle structure separating apparatus 90 attached to the yoke 84.
The yoke 84 in all of its embodiments may optionally incorporate a second self-contained LED 92 attached to a visible portion of the yoke 84 to indicate the yoke's location in a vehicle or container when assembling the stored quick disconnect implement unit 22 to the hydraulic thrust apparatus 20.
The quick disconnect implement unit 22 in the first embodiment, as illustrated in
The tethered yoke pin 88 in this first spreader arms embodiment includes a third self-contained LED light 100 within a head portion of the pin 88 and an adjustable ball lock detent 64 on the distal end.
The vehicle structure separating apparatus 90 in the spreader arm embodiment 94 consists of a pair of opposed spreader arms 102 attached to the yoke 84 and also each connecting link 50. Each spreader arm 102 consists of a steel spreader member having full length teeth and annealed tips that are pinned and bonded to a spreader arm aluminum body.
The spreader arms 102 contain force load gauge indicia 104 on an exposed surface to indicate the amount of force available at a given point relative to a pivot point distance. Each arm 102 incorporates an internal energy absorbing member 106 disposed in a groove flush with an underside external surface. Alternately, the force load gauge indicia 104 may be etched, silk screened, stenciled or attached with a decal, name plate, or the like, to any part of the hydraulic rescue tool 10 displaying the same information, as illustrated in
The quick disconnect implement unit 22 in the second embodiment, as illustrated in
The tethered yoke pin 88 in this cutter jaws embodiment 108 includes a self-contained third LED 100 within a head portion of the pin 88 and an adjustable ball lock detent 64 on the opposite end.
The vehicle structure separating apparatus 90 specifically consists of a pair of cutting blades 126 with each cutting blade 126 having a top member 128 and a bottom member 130. The two members 128, 130 are attached together to form a double thick blade with the top member 128 smaller than the bottom member 130 and the bottom member 130 having an annealed tip. Each member incorporates an internal energy absorbing member 106 disposed flush on an underside surface. The internal energy absorbing member 106 is constructed of flat malleable mild steel, welded in place on an interface surface to the one of the members 128 and 130. The double thick cutting blades 126 engage together in mirror image sets such that the bottom members 130 engage contiguously.
Force load gauge indicia 104 may be located on an exposed surface of the blades 126 or tool 10 to indicate the amount of force available at a given point relative to the pivot point distance.
The quick disconnect implement unit 22 in the third embodiment, as illustrated in
The tethered yoke pin 88 incorporates a third self-contained LED light 100 within a head portion of the pin 88 and a ball lock detent 64 is positioned on the pin's opposite end.
The vehicle structure separating apparatus 90 consists of a pair of opposed spreader arms 138, with each arm having a first end 140 and a second end 142. Each second end 142 is pivotally attached to each connecting link 50, with a bridge 146 attaching each pair of spreader arms 138 together and held captive with the removable link pins 60 such that each spreader arm 138 is free to swivel.
The pusher cam yoke 84a has a triangular shaped body with triangular surfaces contiguously engaging opposed spreader arms 138. The pusher cam yoke 84a is integrally formed with a cylindrical shank 148 for attachment to the piston rod 30 which is disposed within the hydraulic cylinder body 24.
Each spreader arm 138 includes rollers 150 that are configured to interface with the pusher cam yoke 84a defining an initial thrust mode and each spreader arm 138 includes a slot 152 providing an attachment opening for the linkages 136 when axially spreading the arms 138 apart, thereby producing a secondary thrust of the tool. The linkages 136 are configured as toggle links, each having a rectangular shape with raised bosses on one side at opposed ends and are configured to penetrate and slide within the slot 152 in each spreader arm 138 and are attached to the yoke mating through-holes 134.
The quick disconnect implement unit 22 in the fourth embodiment, as illustrated in
The vehicle structure separating apparatus 90 consists of a slotted stop 156 that is aligned with the integral blade 84b of the hub, when the blade is urged within the slot of the stop 156 a severing action occurs such as that created by a guillotine. The yoke with the hub and integral blade 84b is preferably a unitary steel construction, with the hub of the yoke 84 attached to the piston rod 30 with the tethered yoke pin 88. The blade of the yoke 84 has a radially offset crescent-shaped point 158 protruding from a straight edge, with both the point and straight edge having a sharp edge.
The slotted stop 156 consists of a notched top member 160, a notched bottom member 162 and two grooved stop extension arms 164. The extension arms 164 are attached with threaded fasteners 98 on each notch of the top member 160 and each notch of the bottom member 162, leaving a slot 166 therebetween.
Each extension arm 164 is preferably in the shape of a bar with a first end 168, a second end 170 and sides, and the extension arm 164 incorporates a longitudinal groove 172 extending the full length of at least one side. Each extension arm has a bolt hole 174 on the first end 168 and the second end 170 is configured to fit into the clevis end 56 of the connecting link 50. The extension arm first end 168 interfaces with notches in the notched top member 160 and the notched bottom member 162, as illustrated in FIG. 7, and attaches with threaded fasteners 98.
The quick disconnect implement unit 22 in the fifth embodiment, as illustrated in
The vehicle structure separating apparatus 90 consists of a slotted C-shaped jaw 178 configured to receive the blade 84b. When the blade 84b is urged within the jaw slot a severing action occurs such as that created by a guillotine.
The yoke with a hub and integral blade 84b is preferably a unitary steel construction, with the hub of the yoke 84b attached to the piston rod 30 with the tethered yoke pin 88. The blade of the yoke 84b has a radially offset crescent-shaped point 158 protruding from a straight edge with both the point and straight edge having a sharp edge.
The slotted C-shaped jaw is preferably made with an offset tapered top plate 180, and a tapered bottom plate 182 in mirror image of each other. The top plate 180 and bottom plate 182 contiguously engage together with jaw spacers 184 and the C-shaped jaw 178 is configured to permit the hub of the yoke 84 to penetrate therethrough. The C-shaped jaw 178 is attached to the connecting links 50 of the hydraulic thrust apparatus 20 on the top and bottom of the clevis end 56.
The top plate 180 and the bottom plate 182 each include an internal energy absorbing member 106 constructed of flat malleable mild steel, which is welded in place on an exposed internal surface facing each other.
The quick disconnect implement unit 22 in the sixth embodiment, as illustrated in
The yoke 84 is configured with unitary steel construction with a flattened hub attached to the piston rod 30. The tethered yoke pin 88 has a self-contained third LED light 100 within a head portion of the pin 88 and an adjustable ball lock detent 64 on the distal end.
The yoke 84 in this embodiment is different than the previous embodiments in that it is specifically designated as a blade containing yoke 192 configured with an integral elongated channel-shaped blade retainer 194 that is integrally formed in a flattened hub 196. The blade retainer 194 includes a number of blade connecting through-holes 198 for retaining the hooked blade 188 with threaded fasteners 98.
The hooked blade 188 is formed of two discreet flat blade body members 188a and 188b that are juxtapositioned together, as illustrated in
In either case an internal energy absorbing member 106 is disposed in a groove flush with a mating surface on each discreet flat blade body member 188a and 188b. The energy absorbing member 106 is preferably constructed of flat malleable mild steel that is welded in place. The plurality of fasteners 98 attach the blade body to the yoke.
The slotted barrier block 190 consists of a rectangular body having gripping teeth 206 formed in the front surface of the body with a centrally located blade slot 208 therethrough that is configured to provide a slide fit for the blade 188. The barrier block 190 is also configured on each side to interface with the connecting links 50 with the removable link pins 60.
The quick disconnect implement unit 22 in the seventh embodiment, as illustrated in
The vehicle structure separating apparatus 90 incorporates a U-shaped jaw 212 and a pair of compression arms 214 separated by a cutting blade 216 extending within the U-shaped jaw 212.
The C-shaped yoke 110 incorporates a recessed register 114 adjacent to the bottom through-hole 112, with a shoulder bolt 116 having a head 118 on a first end and threads 120 on a second end, disposed within the through-holes 112. A plurality of flat bearings 122 are disposed between the yoke 110 and the compression arms, also a plurality of flat bearings 122 are disposed between the compression arm 214 and the cutting blade 216. A flanged nut 124 is attached to the shoulder bolt 116 on the threaded end. The flange of the nut 124 interfaces with the recessed register 114 of the yoke 110 providing a space that permits a preload, thereby allows each compression arm 214 and the cutting blade 216 to move freely without binding, yet sufficiently close to cut cleanly.
The tethered yoke pin 88 includes a third self contained LED 100 within the head portion of the pin 88 and an adjustable ball lock detent 64 on the opposite end of the pin 88.
The compression arms 214 preferably have a crescent shaped inner edge and a contoured outer edge adjacent to an interface with said U-shaped jaw 212. The cutting blade 216 preferably has a configuration in mirror image of the compression arms 214 with an edge penetrating the compression arms 214 having a sharp cutting edge 218 permitting the cutting blade 216 to penetrate and sever a workpiece when the arms 214 and blade 216 are pulled together by the hydraulic thrust apparatus 20.
The compression arms 214 have a front end 220 and a rear end 222 with the front end 220 penetrating through the U-shaped jaw 212 and extending therein with the rear end 222 having a yoke hole 224 for connecting to the shoulder bolt 116 disposed within the yoke in-line through-holes 112. A caming projection 226 is integrally formed and extends outward from the yoke hole 224 for caming the arms 214 together when the yoke 110 is extended from the hydraulic thrust apparatus 20 with the caming projections 226 interfacing with the U-shaped jaw 212.
The cutting blade 216 also has the same front end 220 and rear end 222 with the front end 220 penetrating through the U-shaped jaw 212 and extending therein. The rear end 222 also has a yoke hole 224 for connecting to the shoulder bolt 216. A caming projection 226 also extends outwardly from the yoke hole 224 caming the cutting blade in like manner as the compression arms 214.
The U-shaped jaw 212 is formed with a jaw body 228 which has a front end 230 and a rear end 232 which faces the hydraulic thrust apparatus 20.
The jaw body 228 incorporates the following features: a connecting link notch 234 on each rear end corner, a front end latch groove 236 through the front end, a plurality of side roller recess opening 238, an arm and blade slot 240 completely through the rear end, and a caming recess 242 in the rear end interfacing with each caming projection 226 on the compression arms 214 and cutting blade 216.
A roller pin 150 captivated by a pair of oil impregnated bushings is pressed into each side roller recess opening 238 in the U-shaped jaw 212 with each roller pin 150 having a groove adjacent to each end with a snap ring disposed within each groove for retention of the pin 150 within the U-shaped jaw 212.
A detachable latch 244 disposed within each U-shaped jaw front end latch groove 236 for strengthening the jaw's open end, with the latch 244 attached through the jaw 212 with a number of tethered quick release latch pins 246.
While the invention has been described in detail and pictorially shown in the accompanying drawings, it is not to be limited to such details, since many changes and modifications may be made to the invention without departing from the spirit and scope thereof. Hence, it is described to cover any and all modifications and forms which may come within the language and scope of the appended claims.
| Number | Name | Date | Kind |
|---|---|---|---|
| 2447401 | Ferguson et al. | Aug 1948 | A |
| 3570835 | McPherson | Mar 1971 | A |
| 3819153 | Hurst et al. | Jun 1974 | A |
| 4333330 | Porter | Jun 1982 | A |
| 4392263 | Amoroso | Jul 1983 | A |
| 4506445 | Esten | Mar 1985 | A |
| 4734983 | Brick | Apr 1988 | A |
| 4886635 | Forster et al. | Dec 1989 | A |
| 5301533 | Jackson | Apr 1994 | A |
| 5425260 | Gehron | Jun 1995 | A |
| 5544862 | Hickerson | Aug 1996 | A |
| 5622353 | Painter et al. | Apr 1997 | A |
| 5956992 | Patton | Sep 1999 | A |
| 6244568 | Patton | Jun 2001 | B1 |
| 7107812 | Patton | Sep 2006 | B1 |
