US3837076A

US3837076A - Power operated portable shear device

Info

Publication number: US3837076A
Application number: US00289115A
Authority: US
Inventors: L Good
Original assignee: Individual
Current assignee: Individual
Priority date: 1972-09-14
Filing date: 1972-09-14
Publication date: 1974-09-24
Anticipated expiration: 1991-09-24

Abstract

A portable cutter unit is operated by fluid pressure from a pump, such as the water pump on a fire engine. An intensifier unit is connected between the pump and the cutter unit, and functions to generate relatively high operating fluid pressure from the relatively low fluid pressure produced by the pump to operate the cutter unit, the intensifier unit including a pilot valve operable from the portable cutter unit. The cutter unit includes interchangeable scissors-type and anvil and blade-type heads, for use in cutting light and heavier materials, respectively.

Description

United States Patent 1 Sept. 24, 1974 Good, Jr.

[ POWER OPERATED PORTABLE SHEAR DEVICE [76] Inventor: Lewis B. Good, Jr., 145 Johnson,

East Peoria, 111. 6161 1 [22] Filed: Sept. 14, 1972 [21] Appl. No.: 289,115

[52] US. Cl 30/180, 30/228, 60/547, 173/169 [51] Int. Cl B26b 15/00, B26b 17/00, B25f 3/00 [58] Field of Search 30/180, 228, 210; 173/169; 60/547, 571, 593; 169/24 [56] References Cited UNITED STATES PATENTS 2,602,224 7/1952 McKay 30/228 2,814,872 12/1957 Gerrans 3,177,584 4/1965 Cockerill 3,495,330 2/1970 Bruce 30/180 3,670,411 6/1972 Peters 30/180 FOREIGN PATENTS OR APPLICATIONS 1,083,767 6/1960 Germany 60/571 Primary Examiner-Al Lawrence Smith Assistant Examiner-J. C. Peters Attorney, Agent, or FirmBacon & Thomas [5 7 ABSTRACT A portable cutter unit is operated by fluid pressure from a pump, such as the water pump on a fire engine. An intensifier unit is connected between the pump and the cutter unit, and functions to generate relatively high operating fluid pressure from the relatively low fluid pressure produced by the pump to operate the cutter unit, the intensifier unit including a pilot valve operable from the portable cutter unit. The cutter unit includes interchangeable scissors-type and anvil and blade-type heads, for use in cutting light and heavier materials, respectively.

15 Claims, 24 Drawing Figures PATENTED BET 24 \974 SHEEI 1 0F 7 PAIENIEU 35 241914 SHEET 6 [IF 7 mw g PAIENIEDSEPZWH 3.887. 016 I SHEEI 7 OF 7 I POWER OPERATED PORTABLE SHEAR DEVICE BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to portable cutter or shear devices for use in the field. More particularly, it relates to a power operated portable shear device especially adapted for use by fire and rescue personnel at the scene of an accident or disaster, and which is capable of generating relatively high cutting forces from the relatively low water pressure produced by the water pump of a tire engine.

2. Description of the Prior Art There is frequent need at the scene of automobile accidents and other disasters for a rescue worker to cut through metal and other materials, to reach trapped victims or simply to gain access to an area. When saws, axes and other manual tools are used for this purpose, not only can the task take an inordinate amount of time, but further injury to a trapped victim can occur. In some instances, acetylene torches are used to cut through metal, but again such must be used with care to avoid injury to a victim. In addition, a torchcannot be employed where the danger of fire or explosion exists.

The use of tools powered by electric motors, while feasible in some instances, is not a fully acceptable alternative to manual tools and acetylene torches, for two principal reasons. First, there may or may not be sufficient electric power available at the accident or disaster scene; the uncertainty as to adequate electric power renders such electric motor-driven tools unreliable, and thus not fully acceptable for rescue work. Secondly, as with acetylene torches, the use of electric motors in an environment where explosive or flammable vapors are present is dangerous. and, therefore, unacceptable.

For all of these reasons, there is need for a portable, power driven cutting or shear device capable of quickly cutting through metal and other materialsfone which will not cause injury to trapped victims, and which offers no hazard when working in an explosive or flammable environment. The present invention is intended to satisfy that need.

SUMMARY OF THE INVENTION The portable rescue shear device of the present invention includes a cutter unit that is connected through an intensifier unit to a fluid pump, such as the pump carried by a fire engine for pumping water through a hose line. The cutter unit is compact and relatively light in weight so that it can be easily manipulated by a rescue worker, and includes a housing equipped with a handle, and to which a selected cutter head is detachably connected. The invention includes cutter heads of the scissors type and the anvil and blade type, and such are easily interchanged. The scissors type cutter head is intended for use on thin sheet metal and like material, while the anvil and blade type cutter head is effective on bar stock and other relatively thick materials.

The cutter unit housing contains a power cylinder housing a power piston, to which one end of a power shaft or ram is connected. The other end of the ram is detachably connectible to the cutter head, for operating the same in response to movement of the piston.

The power piston is operated by fluid pressure conducted to, and from the cutter unit by flexible pressure supply lines.

While the cutter unit must be ruggedly constructed to withstand the forces placed thereon during use, it must also be compact in size for ease of handling. Thus, the size of the power piston is limited. This size limitation on the power piston is of importance because the fluid pressure generated by the usual fire engine pump, while more than adequate for fighting tire, is relatively low for operating a shear cutting unit. Normally, this relatively low pressure could be accommodated in a shear cutter unit by the use of a relatively large piston, taking advantage of the known pressure times area relationship for force generation. But, because the need for a compact cutter unit in the present invention dictates a relatively small power piston, this cannot be done. This is why the intensifier unit is provided between the pump and the cutter unit.

The intensifier unit includes a main housing containing a relatively large main cylinder within which a main piston is slidably received. In the preferred embodiment of the invention the main housing has two confronting power chambers of relatively small diameter, and the main piston carries two oppositely directed small diameter plungers, one being received in each power chamber. Amain valve mounted on the main housing is operated by a pilot valve to admit fluid from the pump to one side or the other of the main piston. The power chambers are connected in a closed loop with the power cylinder containing the power piston of the cutter unit, which loop is filled with a suitable hydraulic fluid. Thus, when the relatively low fluid pressure from the pump acts on the relatively large main piston to move one of the small diameter plungers into its power chamber, the other plunger is simultaneously moved outwardly within its chamber, and hydraulic fluid under a relatively high pressure is supplied to the power piston of the cutter unit for operating the cutter head. In this way the relatively low fluid pressure from the fire engine or other pump is intensified, and used to generate a relatively large force at the cutter head. In the preferred embodiment of the invention the pilot valve is hydraulically operated from a control valve mounted on the cutter unit, so that the rescue worker has full control over the operation of the power operated shear device. The control valve is supplied pressure from the same fire engine or other pump, and is manipulated to supply operating fluid to the pilot valve, which in turn activates the main valve of the intensifier unit. The pilot valve is also equipped with a handle for manual operation, which handle can be locked in a neutral position to thereby immobilize the rescue shear device. I

The intensifier unit is equipped with pressure relief valves to guard against excessive pressures, and a pressure test unit is mounted on the inlet side of the main valve for determining and adjusting the fluid pressure supplied from the pump. In addition, the fluid supply lines are fitted with fuse elements-that will rupture if excessive line pressure should occur. These fluid pressure fuses provide backup to the pressure relief valves, in case the latter should become corroded or damaged.

The power piston of the preferred embodiment is double acting, to provide positive and forceful action on both the forward and the withdrawal strokes of the ram. In one modification of the invention, however, a

single action power piston is employed. In this instance, the power piston is retracted by a spring, andthe intensifier unit is supplied with only one power chamber and plunger. In another embodiment of the invention, the hydraulically operated pilot valve is replaced by an electrical activator, which arrangement may be preferable in some instances.

It is also to be understood that while the invention will be'described primarily as a rescue shear device for use by fire and rescue workers, it can also be used in other situations. For example, the present portable power shear would be well-suited for use in a scrap metal reclamation yard. When used for such other purposes, it is understood that fluid operating pressure would be supplied by some suitable pump arrangement.

It is the principle object of the present invention to provide a powerful portable rescue shear device that fan be easily used by rescue workers and others wherever desired, one which is capable of quickly cutting or shearing metal or other wreckage away from trapped victims at the scene of automobile, airplane, train, boat and other accidents or disasters, and which is safe to use in an explosive or flammable environment.

Another object is to provide a portable, power operated shear device that can be easily manipulated and controlled by one operator.

A further object is to provide a power shear device equipped with two types of easily interchanged cutter heads, a scissors type head for cutting sheet metal and other light materials, and an anvil and blade type head for cutting or shearing heavy materials.

Yet another object is to provide a portable power shear device which is powered by a pump such as is used by firemen for the purpose of pumping water through hose lines, and which can be used simultaneously with the supplying of water to such hose lines.

Still another object is to provide a portable shear device that requires a minimum of instruction and physical ability to use, and which can be used to advantage in situations apart from rescue work.

Other objects and many of the attendant advantages of the invention will become readily apparent from the following description of the Preferred Embodiments, when taken together with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a diagrammatic plan view illustrating one embodiment of the power shear device of the present invention as such might be used by a rescue worker at an accident scene, the device being operated by fluid pressure from a pump carried on rescue vehicle;

FIG. 2 is an enlarged plan view of the cutter unit of the shear device of FIG. 1, the unit being fitted with a scissors-type cutter head;

FIGS. 3A and 3B are enlarged fragmentary transverse-sectional views taken on the lines 3A-3A and 3B-3B, respectively, of FIG. 2; and show the construction of the control valve;

FIG. 4 is a fragmentary side elevational view, partly in section, taken on the line 4-4 of FIG. 2;

FIG. 5 is a fragmentary bottom view of the cutter head of FIG. 4, showing how such is detachably mounted;

FIG. 6 is a fragmentary top plan view of the cutter unit of FIG. 1, equipped with a modified form of cutter head of the anvil and blade type; 1

FIG. 7 is a fragmentary side elevational view of the cutter head of FIG. 6;

FIG. 8 is' a vertical sectional view, taken on the line 88 of FIG. 7;

FIG. 9 is an enlarged plan view of the intensifier unit 0fFlG.l; r I:

FIG. 10 is an elevational view, partly in section, of the intensifier unit of FIG. 9;

FIG. 11 is a fragmentary horizontal sectional view through the pilot valve of the intensifier unit, taken on the line 11l-1 of FIG. 10, and showing the valve in its closed or OFF". position;

FIG. 12 is a fragmentary horizontal sectional view, similar to FIG. 11, but showing the pilot valve in its open or ON position;

FIG. 13 is an enlarged fragmentary, horizontal sectional view through the main valve of the intensifier unit, taken on the line 13-13 of FIG. 10;

FIG. 14 is an enlarged, fragmentary, horizontal sectional view taken on the line 14-14 of FIG. 10, further showing construction of the main valve;

FIG. 15 is a fragmentary, vertical sectional view taken on the line 15-15 of FIG. 10, through the pilot valve and the main valve;

FIG. 16 is a perspective view of the valve core of the main valve;

FIG. 17 is a schematic view of the hydraulic control circuit for the portable power shear device of FIG. 1;

FIG. 18 is a schematic view of a modified form of control circuit for the power shear device, wherein an electric actuator is substituted for the pilot valve;

FIG; 19 is a schematic view of a modified power shear device, utilizing a single action power piston in the cutter unit;

FIG. '20 is an enlarged fragmentary side elevational view, partly in section, of the cutter unit of the embodiment of FIG. 19;

FIG. 21 is an enlarged, fragmentary elevational view of a second embodiment of the main valve, which may be preferred in some uses;

FIG. 22 is a horizontal sectional view taken on line 2222 of FIG. 21; and

FIG. 23 is a perspective view of the valve element of themain valve of FIGS. 21 and 22.

DESCRIPTION OF THE PREFERRED EMBODIMENTS a rescue vehicle 14. I

The cutter unit 4 is shown in detail in FIGS. 2-5, and includes an elongated housing 16 terminating at the forward end'in a generally cubical mounting head 18, and which contains a cylindricai bore 20. The cylindrical bore 20 is divided by a wall 22 into a forward power cylinder 24 and an aft cylindrical valve chamber 26, the latter being open at its outer end. A power piston 28 is slidably received within the power cylinder 24, and carries a sealing ring in an annular groove on the cylindrical surface thereof. The power cylinder 24 extends partly into the mounting head 18, and the latter has a reduced diameter cylindrical bore 32 extending therethrough aligned on the axis of the power cylinder 24, said bore 32 having an annular groove therein for reception of an O-ring seal 33. A power shaft or ram 34 is connected at its rear end to the power piston 28 and extends forwardly through the bore 32, the forward or outer end of the ram 34 carrying a bifurcated head or connecting yoke 36 having aligned bores in the legs thereof for receiving a connecting pin 38.

The power piston 28 is of the double acting type, and for this purpose the housing 16 has two supply ports 40 and 42, the port 40 being located on the mounting head 18 and opening into the forward section of the power cylinder 24, and the port 42 opening into the aft section of the power cylinder.

Fluid conduits

44 and 46 are connected to the supply ports 40 and 42, respectively, and lead to the intensifier unit 10, the

conduits

44 and 46 being embodied in the combined hose line 8.

The cutter unit 4 of FIGS. 1-5 is equipped with a cutter head 48 of the scissors type, for use on sheet metal and the like. The mounting head 18 is designed so that the cutter head 48 can be easily and quickly mounted or dismounted, and for this purpose has a rectangular, transversely extending recess 50 cut in the flat bottom face 52 thereof. A rectangular channel 54 extends from the recess 50 to the vertical flat front face 56 of the head 18, and the end walls of the recess 50 have centrally disposed, aligned, tapered frusto-conical bores 58 therethrough for receiving tapered connecting pins 60. The channel 54 is offset from the center of the mounting head 18.

The cutter head 48 includes a mounting bracket 62 having a rectangular base portion 64 that is snugly received in the rectangular recess 50, and a rectangular arm portion 66 connected with the base portion 64 and which extends forwardly through the channel 54. The end walls of the base portion 64 have tapered bores 68 therein for receiving the tapered connecting pins with a wedge fit, whereby the bracket 62 is rigidly but detachably secured to the mounting head 18.

The arm 66 has a lateral offset 70 therein, and terminates at its outer end in a pair of upstanding cars 72 having aligned bores therein for receiving a pivot pin 74 that connects the midportions of upper and

lower scissors blades

76 and 78, respectively, thereto. The forward ends of

drive links

80 and 82 are connected by pivot pins 84 to the rear ends of the upper and

lower scissors blades

76 and 78, respectively, and the rear ends of the

links

80 and 82 are pivotally mounted on the connecting pin 38, Thus, when the ram 34 is advanced, the forward cutting edges of the

scissors blades

76 and 78 will separate, the forward portion of the arm 56 having a cutout 85 therein to accommodate downward movement of the rear end of the upper blade 76 and its link 80. When the ram 34 is then retracted, the cutting surfaces of the

blades

76 and 78 will move toward each other to effect shear cutting of any material placed therebetween.

Referring now to FIGS. 1 and 9-17, the intensifier unit 10 includes a main housing 86 having a base flange 88 and containing a main cylinder 90, the cylinder 90 including a cylindrical bore 92 extending into the main housing 86 from one end face 94 thereof, and which terminates in a reduced diameter manifold chamber 96. The open end of'the main housing 86 is closed by a cover plate 98 secured by bolts 100, an annular gasket 102 being disposed between the cover plate 98 and the end face 94, and the cover plate 98 carrying an annular boss 104 thereon that forms a manifold chamber 106.

The rear face 108 of the main housing 86 has an axially extending cylindrical housing 110 thereon, and the cover plate 98 bears a similar, aligned cylindrical housing 112. The

cylindrical housings

110 and 112 contain axially aligned,

cylindrical power chambers

114 and 116, respectively, that open into the main cylinder 90 and which are threaded internally at their outer ends to receive

fittings

118 and 120, respectively. A main piston 122 carrying a sealing ring 124 in an annular groove on the cylindrical surface thereof is slidably received within the main cylinder 90, and has oppositely extending, axially aligned

plungers

126 and 128 thereon that are slidingly received in the

power chambers

114 and 116, respectively. The

plungers

126 and 128 and their

power chambers

114 and 116 are of such length that the main piston 122 can move the length of the main cylinder 90, with the plungers remaining slidably engaged within their respective power chambers. O-

ring seals

127 and 129 are carried in annular grooves on the outer ends of the

plungers

126 and 128, respectively, to prevent fluid pressure from leaking between the main cylinder 90 and the outer ends of the

power chambers

114 and 116.

The forward section of the power cylinder 24 of the cutter unit 4is connected by the conduit 44 to the fitting 118 on the power chamber 114, and the aft section of said power cylinder is connected by the conduit 46 to the fitting 120, all in a closed loop system containing a given volume of hydraulic fluid, the closed loop including a reservoir 130 connected with the

conduits

44 and 46 through one-

way check valves

132 and 134, respectively (FIG. 17). Thus, when the main piston 122 is driven to move the plunger 126 into the power chamber 114, the check valve 132 remains closed, and hydraulic fluid is forced under pressure into the forward end of the power cylinder 24, thereby urging the ram 34 to retract. Simultaneously, hydraulic fluid from the decreasing in volume aft end of the power cylinder 24 is transmitted to the expanding power chamber 116 through the conduit 46, the check valve 134 allowing replacement fluid to be added to the system if needed. Similar operation in the opposite direction occurs when the main piston 122 is driven the opposite way, whereby operation of the shear cutting unit 48 is obtained.

The main piston 122 is operated by fluid pressure admitted to the manifold chambers 96 and 106 at the opposite sides thereof through

fittings

136 and 138, and the transmission of such operating fluid is controlled by a main valve 140 that in turn is operated by a pilot valve 142. The main valve 140 includes a cylindrical body 144 having a cylindrical bore 146 extending therethrough, and terminating at its lower end in an external flange 148. The flange 148 is secured by bolts 150 to the top surface 152 of the intensifier main housing 86, an annular gasket 154 being interposed therebetween.

The side wall of the cylindrical body 144 has two axially spaced, parallel supply and discharge arc chambers I 156 and 158 cut or cast in the exterior, said grooves extending for 90 degrees and being covered by welded in place

arcuate strips

160 and 161, respectively. At the ends of the upper or supply are chamber 156 radial ports 162 and 164 extend into the body 144, and similar ports 166 and 168 are disposed at the opposite ends of the lower or discharge are chamber 158. Diametrically opposite the vertically aligned

ports

162 and 166 the body 144 has a vertical chamber 170 therein, and inwardly directed

ports

172 and 174 leading to said chamber 170 are arranged to diametrically confront the

ports

162 and 166. Similarly, a vertical chamber 176 is disposed opposite the vertically aligned ports 164 and 168, and connecting

ports

178 and 180 confront said ports 164 and 168, respectively. Obviously, all internal passages can either be drilled, or they can be provided during casting.

A rotary valve core 182 is received in the housing 140, and has two vertically spaced diametric bores 186 and 188 extending therethrough which extend at right angles to each other. The upper bore 186 is arranged to connect either the ports 178 and 164 or the

ports

162 and 172, depending upon the rotary position of the valve core 182, and the lower bore 188 is arranged to connect either the ports 168 and 180 or the

ports

166 and 174. The

bores

186 and 188 have O-

ring seals

187 and 189, respectively, seated in annular grooves at the opposite ends thereof, to prevent excessive pressure losses.

Referring now to FIG. 17, the intensifier unit 10 is supplied with water pressure from the pump 12, which is connected to a water supply tank 190 carried by the truck 14, and driven by a motor 192, which can be the motor of the truck 14 or a separate ,unit. The pump 12 also includes an inlet 194 and a discharge 196, the pump inlet 194 being connected by a conduit 198 to the discharge are chamber 158 of the main valve 140, and the pump outlet being connected to the main valve supply are chamber 156 by a conduit 200.

The vertical valve chamber 170 is connected by a conduit 202 to the fitting 136 leading to the manifold chamber 96, and similarly a conduit 204 connects the fitting 138 to the valve chamber 176. The

conduits

202 and 204 have

pressure relief valves

206 and 208, respectively, therein to prevent an excessive pressure I build-up in the device. As further insurance against damage from excessive pressure,

frangible fuse elements

210 and 212 are disposed in the

lines

202 and 204, respectively, and are chosen to fracture at a pressure greater than the setting of the

relief valves

206 and 208.

The main valve 140 is operated by the pilot valve 142, the latter including a lower cup-shaped body member 214 having a flange 216 thereon which is secured to the open upper end of valve body 144 by bolts 218, a gasket 220 being interposed therebetween. The lower body member 214 contains a circular working chamber 222, and has an axial bore 224 in the bottom wall 226 thereof. An operating shaft 228 is secured by a key 230 within an axial socket 232 in the valve core 182, and projects upwardly through the bore 224. An O-ring seal 234 is carried within a groove in the wall of the bore 224, and seals the lower end of shaft 228.

An upper body member 236 having an open-ended chamber 238 therein and a projecting flange 240 is secured to the upper surface of the lower member 214 by bolts 242, the top wall 244 of the chamber 238 having a socket 246 therein for seating the upper end of the shaft 228. An O-ring seal 235 is carried in a groove in the wall of chamber 238, to seal the upper end of shaft 228.

The side wall of the body member 236 has a circumferential slot 248 therein, which extends for degrees, and which has an enlarged seat portion 250 positioned centrally thereof. The threaded inner end of a manual operating handle 252 projects through the slot 248 and is threaded into a radial bore 249 in the operating shaft 228, whereby the operating shaft 228 and the valve core 182 can be rotated over the 90 allowed by the length of the slot 248. A lock nut 254 (FIG. 11) is threaded on the operating handle 252, and is receivable within the seat 250 when the handle 252 is midway the slot 248 to lock the operating valve in a neutral position.

The main valve can be operated by the handle 252. When the lock nut 254 is seated in the enlarged seat portion 250, the

axial bores

186 and 188 of the valve core 182 are out of communication with all of the

ports

174, 180, 166, 168, 172, 162, 178 and 164. After the lock nut 254 has been retracted, when it is desired to retract the ram 34 and thereby operate the cutting shears 48, the handle 252 is moved on the ON end of the slot 248, whereby the upper valve core bore 186 is moved to connect the port 164 with the port 178 and fluid under pressure is supplied to the manifold chamber 106 through the conduit 204. Simultaneously, the lower valve core bore 188 connects the ports 174 nd 176, whereby the manifold chamber 96 is connected to the discharge chamber 158 by the conduit 202.

The main piston 122 is thereby driven toward the power cylinder 114, whereby high fluid pressure is transmitted to the power chamber 24 by the conduit 44. When the main piston 122 has travelled fully toward the cylinder 114, pressure therebehind is relieved through a bleed port 256 positioned at the center of the main chamber 90. The bleed port 256 connects with a passage 258 in the main valve body 140 and which leads to the discharge chamber 158.

Movement of the cutting head power ram 34 in the opposite direction is achieved by moving the operating handle 252 to the opposite or OFF" end of the slot 248, as will be obvious. While such manual operation of the shear unit from the location of the intensifier unit 10 is possible and may be desirable in some instances, automatic operation from the shear unit is usually preferable.

To provide such automatic operation, the portion of the operating shaft 228 received in the chamber 222 has a radial vane 260 thereon, the outer surfaces 262 of which carry a seal 263 and engage the three walls of the chamber 222. The cylindrical wall of the chamber 222 has a similar vane 264 affixed thereto by screws 266, although it could be formed integrally if desired, the vane 264 dividing the interior of the chamber 222 into two pressure chambers 268 and 270 (FIG. 12).

Fittings

272 and 274 are connected to the

chambers

268 and 270, respectively,foroperating the vaned operating shaft 228. When the lock out 254 is retracted, the operating shaft 228 can be rotated in either direction to the limits provided by the ends of slot 248 and the handle 252 by alternately connecting one of the

fittings

272 or 274 to' a supply of fluid pressure while the other is connected to'drain, as will be apparent from a study of the drawings.

The flow of fluid pressure to and from the

pilot valve chambers

268 and 270 is controlled bya control valve 276 carried by the cutter unit 4. The valve housing of the control valve 276 is the aft portion of the elongated housing 16 containing the cylindrical bore section 26, said housing having forward and aft parallel, axially spaced

arcuate passages

278 and 280 cut therein, the passages extending 90 and being covered by welded in

place plates

282 and 284, respectively.

Radialports

286 and 288 extend inwardly from the opposite ends of the aft arcuate passage 278, and similarly

radial ports

290 and 292 are disposed atthe oppositeends of the forward arcuate passage-280.

The body 16 has two

axial passages

294 and 296 drilled thereintofrom the aft endof said body, and

which are then-plugged at their outerends. The pas- :sages 294 and 29 6 are spaced 90 degrees, with the passage 294 lying diametrically opposite the

bores

288 and 292, and with radial-ports 298 and300'being arranged to confront said

ports

288 and 282, respectively, the ports 298and 300 beingin communicationtthrough the axial passage 294.'Similarly, the axial passage 296 is diametrically opposite. the

ports

286 and 290,.and communicates with radial-ports 302 and 304'that respectively confront the

ports

286 and 290. A fitting 306 carried by the body 16 communicates-with the axial passage 294, and a similar fitting 308 connects with the axial passage296.

A cylindrical valvestem "310 isdisposed within the bore 26,.and has an enlarged,-=knurledhandle portion 312 on the outer end thereof. The forward :end of the stern 310 has an annular groove 314 therein disposed oppositely threaded bores316 extending throughathe wall of the chamber 26, and the-valve stemis rotatably secured in position by the reduced diameter head portion 318 of screws 320 threaded into the bores 316. The aft or outer end of the bore26 has agroove therein containing an O-ring seal 322, :and rotation of the knurled handle portion 312 is limitedat its opposite positions by stop lugs 313 secured in threaded bores in the housing 16, the stop lugs 313 being spaced-90 degrees apart, and the handle portion 312 carrying a finger 315 engageable with said stop lugs.

The valve stem- 310 has two diametrically disposed and axially spaced

bores

324 and 326 extendingtherethrough, said bores being rotated 90 degrees relative to each other. The bore 324 is arranged toconnect either the

ports

286 and 302 or the ports 288and 2.98, and the bore 326 is arranged to connect either the.

ports

290 and 304 or the ports 292 and 300. Between the bore 326 and the O-ring seal 322 the valve stem 310 has an annular groove 328 therein for collecting any leaked fluid, said groove being connected withthe bore 324 by a drain passage 330.

The forward arcuate-passage 278 isconnected by a conduit 332 to the fluid pressure-supply conduit 200 (FIG. 17), and the aft passage 280 is connected by a conduit 334 to the drain conduit 198. The fitting306 leading to the axial passage 294 is connected by a conter unit with one hand by a handle 340 mounted on the cubical head 18, grasping the handle 3.12 with the other hand to remotely operate the pilot valve 142.

Because the fluid pressure from the pump outlet 196 can vary greatly, it is desirable to determine the value thereof before it is used to operate the shear unit. For this reason, and to prevent accidental injury to the shear operator, the main valve is initially placed in a neutral position by threading the lock nut 254 into the locking space 250 midway of the groove 248. The pressure in the line 200 is then passed through a bypass 'line 342 leading directly to the discharge line .198 (FIG.

17), the supply line 200 having a pressure reducer 344 therein just forward of the bypass line 342.

The bypass line 242 contains a pressure gauge 346 and a shut-off valve 348 connected in series, whereby the supply pressure can be checked and adjusted to a .desired setting. The valve 348 must ,be closed before releasing the lock nut 254 to allow flow to pass into the main valve 140, or a power loss will occur which will adversely affect the operation of the shear unit. The lock nut 254 is then released, the control valve 276 being first placed in a neutral position. Thereafter, the power ram can be activated in either direction by prop- :erly rotating the handle 312 to. remotely operate the pilot valve 142, or the main valve 140 can be operated directly by moving the handle 252 by hand. In either case the

blades

76 and 78, because of the intensifier 1 unit 10, will be operated with considerable force to cut sheet material placed therebetween.

Before the pilot valve handle 252 is manually operated, pressure must be relieved in the

lines

336 and 338. For this purpose, the

lines

336 and 338 are respectively provided with bleed valves 337 and 339 (FIG.

. ing an'upright anvil 408 on the outer end thereof, and

upon which a shear blade 410 is slidably mounted by a tapered keeper 412 riding in a tapered track 414 provided in the side of said arm 406. The rear end of the shear blade is connected directly to the yoke-36 by the pin 38, and the front inner edge 416 thereof is arranged to just slide past the front face 418 of the anvil 408 when the ram 34 is fully advanced. The anvil cutter unit '400 is intended for heavy duty use.

Referring now to FIG. 18,.a further embodiment of the invention is shown wherein the fluid operated pilot valve 142 is replaced by a conventional two directional rotary electric solenoid 500, to which energy is supplied from a power source 502. The rotary solenoid 500 is operated by a control switch 504 mounted on the cutter unit 4', modified to replace the control valve 276 with suitable switches 504 mounted near a handle 506. Otherwise, the structure of FIG. 18 corresponds to that of FIG. 17.

A modification of the cutter unit4 is shown at 600 in FIG. 20, wherein the double-acting power cylinder is replaced by a single acting power piston 602 mounted in a cylinder 604 in the housing 606. A cutter head 605 is mounted on a mounting bracket 630, the bracket 630 being mounted like the bracket 62. The cutter'head 605 includes a pair of

cutter blades

607 and 609, each in the form of a bell crank having

cutter portions

611 and 613 and link attaching portions 615 and 617, respectively. The

blades

607 and 609 are pivotally mounted at the elbow thereof on a pin 619 mounted to extend between upstanding ears 621 on the outer end of the bracket 630, and are pivotally connected through

links

623 and 625 to a pin 603 carried by a yoke 601 mounted on the outer end of a power cam 608 that is connected at its other end to the power piston 602.

Power fluid is supplied behind the power piston 602 through a port 610 and conduit 612, the piston being returned by a coil spring 614 disposed in front thereof. A control circuit for the cutter unit 600 is shown in H6. 19, such being of the electrically operated type shown in FIG. 18.

Referring to H6. 19, because a single action piston 602 is used in the cutter head 600, an intensifier unit 616 with only one power chamber 618 is required, such being operated by a rotary solenoid pilot valve 620 controlled from a switch unit 622 on the cutter head 600. Otherwise, the operation of the arrangement of FIG. 19 is similar to that of FIGS 17 and 18, except that the pressure relief valve 624 in the fluid circuit between the main valve 140 and the intensifier unit 616 is arranged to be electrically operable from a switch 626 on the cutter unit 600 to change the relief valve setting so that both heavy-duty and light-duty shear attachments can be operated safely and effectively, without danger of overload damage and with adequate pressure for maximum effectiveness.

For example, if an operator were using a heavy-duty shear attachment which requires higher pressure, and he changed to a light-duty attachment which operates at a lower pressure, he would need to change the pressure relief valve setting so that pressure would be relieved before damage could occur to the light-duty attachment. On the other hand, if the operator is using a light-duty attachment, and must change to a heavyduty attachment, he would need to change the relief valve setting in order to have sufficient pressure for effective use ofthe heavy-duty attachment. By having the relief valve 624 remotely controlled at the cutter unit no time is lost in changing the relief valve setting for either instance, an important factor under emergency conditions. 7

The spring in the cutter unit of FIGS. 19 and 20 is assisted by atmospheric pressure in opening the cutter blades of the attachment. it is apparent that the shear attachment of FIGS. 19 and 20 is designed to close on the foreward ram stroke, unlike the shear unit 48.

Referring now to FIGS. 21-23, a modification of the main valve is shown at 700, which main valve 700 may be preferred in some instances because it is simpler and somewhat easier to manufacture than the main valve 140. The main valve 700 is operated by a pilot valve 142 like that shown in FIGS. 1'-17, and includes a cylindrical body 702 having a cylindrical bore 704 extending therethrough, the lower end of said body 702 having a flange 706 thereon that is secured by bolts 150 to the intensifier main housing 86. The pilot valve 142 is secured to the top face of the valve body 702 by bolts 218,

suitable gaskets

154 and 220 being utilized to seal the joints.

The valve body 702 has four equally spaced, tapped

ports

708, 710, 712 and 714 therein. The diametrically

opposite ports

708 and 712 are connected by

fittings

716 and 718, respectively, to the

conduits

202 and 204, whereby to conduct flow to and from the opposite sides of the main piston 122 of the intensifier unit 10. The

' prises a diametrical axial section through cylinder having nearly identical dimensions to the cylindrical chamber 704 and includes top and bottom faces 728 and 730, parallel flat sides 723 and 734, and arcuate end faces 736 and 738. O-ring type seals 740 are carried in peripheral grooves on the valve element 726 to seal such with the surfaces defining the cylindrical chamber 704, and said element is secured axially thereof to the lower end of the shaft 228 of the pilot valve assembly The valve element 726 is so dimensioned and fixed to the shaft 228 that when the pilot valve handle 252 is locked in its central or neutral position, the valve element 726 will extend diametrically between the

ports

710 and 714 and will fully block both thereof. Thus, no flow through the main valve can occur. When the handle 252 is then moved to the left in FIG. 21, the valve element 726 will shift to connect the

ports

708 and 710, and the

ports

712 and 714. Rotation of the shaft 228 by degrees in the opposite direction will connect the

ports

708 and 714, and the

ports

710 and 712.

-It is thus readily seen that the main valve 700 provides the same flow control as the main valve 140, while being'of somewhat simpler construction.

Obviously, many modifications and variations of the present invention are possible, without departing from the invention as shown and described.

1 claim:

1. A portable power shear device for forcible entry and rescue work, and used in combination with a fire department pumper truck, said truck including a water pump, said shear device comprising: a portable cutter unit, said cutter unit including: a cutter head; and piston means connected with said cutter head and arranged to operate the same in response to fluid pres sure; fluid pressure intensifier means located remotely from said cutter unit, and connected with said piston means; and means adapted to connect said remotely located intensifier means with said water pump on said truck, said connecting means including valve means operable to actuate said intensifier means for transmitting fluid pressure to said cutter unit piston means, and means for operating said valve means.

2. A portable power shear device as recited in claim 1, wherein said intensifier means includes: a housing containing a relatively large diameter main cylinder and at least one relatively small diameter power chamber; 21 main piston slidably received in said main cylinder; and a plunger carried by said main piston and slidably received within said power chamber, said power chamber being connected with said cutter unit piston means by conduit means containing hydraulic fluid,

and said valve means being operable to control the flow of fluid pressure from said source into said main cylinder for operating said main piston.

3. A portable power shear device as recited in claim 2, wherein said cutter unit piston means is single acting, said piston means being movable in one direction by fluid pressure transmitted thereto from said power chamber of said intensifier unit, and including resilient means for returning said piston means in the opposite direction when said fluid pressure transmitted from said power chamber is relieved.

4. A portable power shear device as recited in claim 2, wherein said cutter unit piston means is double acting and said intensifier means includes two power chambers disposed on opposite sides of said main piston, said main piston carrying two plungers, one plunger being slidably received in each power chamber, said power chambers being connected to the opposite sides of said double acting cutter unit piston means.

5. A portable power shear as recited in claim 1, wherein said cutter head piston means includes a power ram, and wherein said cutter head comprises: a mounting bracket; and cutter means mounted on said mounting bracket and connectible with said power ram.

6. A portable power shear as recited in claim 5, wherein said cutter means comprises a scissors unit.

7. A portable power shear as recited in claim 5,

wherein said cutter means comprises: an anvil fixed to the outer end of said mounting bracket; and a cutter blade slidably mounted on said mounting bracket, and connectible with said power ram.

8. A portable power shear device as recited in claim 1, wherein said intensifier means includes a housing having a relatively large diameter main cylinder and a main piston slidably received within said main cylinder, and wherein said valve means is arranged to control the flow of fluid pressure into said main cylinder from said source of fluid pressure, said valve means including: a main valve including a housing having port and passage means therein; a main valve core received in said main valve housing; said valve core being rotatable between at least one position wherein a flow path is established between said source of fluid pressure and said main cylinder, and a neutral position wherein flow through said main valve is blocked; and means operable to rotate said main valve core.

9. A portable power shear device as recited in claim 8, wherein said means operable to rotate said main valve core includes: an operating shaft connected with said valve core; a housing mounted over the upper end of said operating shaft and having an annular slot in the wall thereof; a handle extending through said slot and engaged with said operating shaft, said slot, said handle and said operating shaft being arranged so that when said handle is positioned at one end of said slot said main valve is open for flow therethrough, and so that when said handle is positioned medially of said slot said main valve core is in said neutral position; and means operable to releasably secure said handle in said neutral position.

10. A portable power shear device as recited in claim 8, wherein said means operable to rotate said main valve includes: an operating shaft connected with said valve core; a fluid operated pilot valve connected with said operating shaft; and a control circuit connected with said source of fluid pressure, and containing a control valve for operating said pilot valve to rotate said main valve in a desired direction, said control valve being positioned on said cutter unit.

11. A portable power shear device as recited in claim 8, wherein said means operable to rotate said main valve includes: an operating shaft connected with said valve core; electric rotary solenoid means connected with said operating shaft; a power supply; and switch means on said portable cutter unit and connected with said power supply and said rotary solenoid means, operable to selectively actuate said solenoid means.

12. A portable power shear device as recited in claim 1, further including pressure control means connected to prevent damage to said cutter unit in case said cutter unit is overloaded.

13. A portable power shear device as recited in claim 12, wherein said pressure control means comprises a pressure relief valve.

14. A portable power shear device as recited in claim 1, wherein said connecting means further includes flowvolume control means to prevent excessive flows from said pump to said intensifier unit.

15. A portable power shear device as recited in claim 1, wherein said connecting means further includes pressure test means.

Claims

1. A portable power shear device for forcible entry and rescue work, and used in combination with a fire department pumper truck, said truck including a water pump, said shear device comprising: a portable cutter unit, said cutter unit including: a cutter head; and piston means connected with said cutter head and arranged to operate the same in response to fluid pressure; fluid pressure intensifier means located remotely from said cutter unit, and connected with said piston means; and means adapted to connect said remotely located intensifier means with said water pump on said truck, said connecting means including valve means operable to actuate said intensifier means for transmitting fluid pressure to said cutter unit piston means, and means for operating said valve means.

2. A portable power shear device as recited in claim 1, wherein said intensifier means includes: a housing containing a relatively large diameter main cylinder and at least one relatively small diameter power chamber; a main piston slidably received in said main cylinder; and a plunger carried by said main piston and slidably received within said power chamber, said power chamber being connected with said cutter unit piston means by conduit means containing hydraulic fluid, and said valve means being operable to control the flow of fluid pressure from said source into said main cylinder for operating said main piston.

7. A portable power shear as recited in claim 5, wherein said cutter means comprises: an anvil fixed to the outer end of said mounting bracket; and a cutter blade slidably mounted on said mounting bracket, and connectible with said power ram.