GB1575232A

GB1575232A - Device for supplying fuel to a combustion engine and method of manufacturing said device

Info

Publication number: GB1575232A
Application number: GB1585/77A
Authority: GB
Original assignee: Holec NV
Current assignee: Holec NV
Priority date: 1976-01-21
Filing date: 1977-01-14
Publication date: 1980-09-17
Also published as: FR2339068B1; GB1575233A; SE8302288D0; IT1082960B; SE435749B; DE2701787A1; SE8302288L; SE7700588L; FR2339068A1; JPS52115924A

Description

(54) DEVICE FOR SUPPLYING FUEL TO A COMBUSTION ENGINE AND METHOD OF MANUFACTURING SAID DEVICE (71) We, HOLEC N.V. a body Corporate organised and existing under the Laws of the Netherlands, formerly of No. 25, Steenbakkersweg, Hengelo, the Netherlands and now of No. 93, Stationsplein, Hoog Catharijne, Utrecht, the Netherlands, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed, to be particularly described in and by the following statement: The invention relates to a device for delivering fuel to a combustion engine, said device comprising at least two pumps each having a pump chamber, a piston and driving means for reciprocatory movement of the piston. Such a device is described in U.S. Patent No.

4022174, the contents of which are considered to be included by reference.

According to the present invention there is provided a device for delivering fuel to a combustion engine, comprising at least one pair of fuel pumps, each fuel pump including a pumping chamber and passages communicating the chamber through an inlet valve with a fuel supply and through an outlet valve with a fuel delivery port to be connected with the combustion engine, each said pumping chamber being variable in volume by a reciprocable displacer body, the displacer bodies of the or each pair of fuel pumps and driving means therefor being intercoupled by means of a coupling member arranged between the two fuel pumps, and wherein the pumping chambers of the or each pair of fuel pumps are provided in a bridge piece comprising two opposed ends interconnected by an intermediate piece, said chambers being bounded within co-axial bores located one in each end of the bridge piece.

The invention also provides a method of manufacturing such a device wherein the bridge piece is made in a body of rigid material by making and broaching a long bore, which is subsequently divided into two coaxial, relatively spaced short bores by milling out material to form a recess between them: The invention will be better understood from the following detailed description which is given by way of example with reference to the accompanying drawings in which:: Fig. 1 is a perspective elevation, partly broken away, of an embodiment of a device in which the provision of pumping chambers in a bridge piece is omitted Fig. 2 is a plan view, partly broken away, of the device shown in Fig. 1, Fig. 3 is an enlarged sectional view taken on the line III-III in Fig. 2, Fig. 4 is a sectional view taken on the line IV-IV in Fig. 2, the device being schematically connected with a combustion engine, Fig. 5 is an enlarged sectional view of a detail V in Fig. 4, Fig. 6 shows an electric circuit diagram for the device shown in Fig. 1, Fig. 7 is an enlarged sectional view taken on the line VII-VII in Fig. 2, Fig. 8 is an enlarged longitudinal sectional view of detail VIII of Fig. 2, Fig. 9 is a longitudinal sectional view of a casting mould for the manufacture of a piston, Fig. 10 is a longitudinal sectional view of a casting mould in the manufacture of a valve, Fig. 11 shows a variant of a detail of Fig. 4 with a circuit diagram, Fig. 12 is a plan view of a further device for delivering fuel to eight atomizers of a combustion engine, Fig. 13 is a sectional view taken on the line XIII-XIII in Fig. 12, the device being schematically connected with a combustion engine.

Fig. 14 is an enlarged sectional view of detail XIV in Fig. 13.

Fig. 15 is a perspective view, partly broken away, of an embodiment of a device in accordance with the invention Fig. 16 is a plan view, partly broken away, of the device shown in Fig. 15, Fig. 17 is a sectional view taken on the line XVII-XVII in Fig. 16, Fig. 18 is a sectional view taken on the line XVI-XVI in Fig. 16, the device being schematically connected with a combustion engine, Fig. 19 is an enlarged sectional view taken on the line XXI-XXI in Fig. 16, Fig. 20 is an enlarged, longitudinal sectional view of detail XX in Fig. 16, Figs. 21, 22 and 23 are perspective views of the detail XX in progressive manufacturing stages, Fig. 24 is a longitudinal sectional view of detail XX in a manufacturing stage subsequent to that of Fig. 23, Fig. 25 is a sectional view taken on the line XXII-XXII in Fig. 16, Fig. 26 shows a variant of the diagram for connecting the device of Figs. 15 to 25 with a combustion engine, Fig. 27 is a plan view of a further developed device embodying the invention for delivering fuel to six atomizers of a 6-cylinder combustion engine, Figure 28 is a perspective elevation, partly broken away, of a further device in which provision of pumping chambers of pumping chambers in a bridge piece is again omitted, Figure 29 is a plan view, partly broken away, of the device of Figure 28, Figure 30 is a sectional view taken on the line XXX-XXX in Figure 29, Figure 31 is a vertical cross-sectional view through the device in Figure 29, showing schematically the connection with a combustion engine, Figure 32 is an enlarged sectional view taken on the line XXXII-XXXII in Figure 29, Figure 33 is an enlarged, longitudinal sectional view of a detail XXXIII in Figure 29, Figure 34 shows on an enlarged scale a detail XXXIV of Figure 33, Figure 35 is a sectional view corresponding to Figure 34 in the dismounted state, and Figure 36 shows a variant of detail XXXVII in Figure 28.

The device 1 shown in Figs. 1 to 8 comprises a frame plate 3 of cast or spray-cast aluminium. Two pairs of electro-magnets 2 are firmly connected by means of bolts 6 between the frame plate 3 and a lid 4. Each of the electro-magnets 2 comprises a core 10 of a stack of magnetic plates 5 and an energizing coil 14 surrounding said core 10. A plate-shaped armature 18 is adapted to oscillate between each pair of alternately energized magnets 2.

At the free end 15 each armature 18 holds a coupling member 20, with which are connected two displacer bodies 22 of two fuel injection pumps 32. The stroke of the displacer bodies 22 is determined by adjustable stroke control means in the form of two wedges 26, 33 disposed on either side of the coupling members 20. Each pump 32 comprises a pump chamber 29 included in a pump housing 42 and having fuel inlet 27 and a fuel delivery conduit 28, each conduit 28 leading to an atomizer 30 of the combustion engine 31. Each atomizer 30 has a sleeve 185 welded to the air inlet manifold 72, in which sleeve an atomizer tube 187 is included by means of a sealing ring 188 and a lid 186. The atomizer tube 187 includes a valve housing comprising an outlet portion 189 externally sealed by a sealing ring 190 and an inlet tube 192.The outlet portion 189 with its seat 191 is made from tool steel and can be manufactured at lower cost than conventional hard-steel seats. The outlet portion 189 is joined by the inlet tube 192 having at its inlet end a transverse groove 193 receiving a transverse pin 194. A tension spring 195 engages this pin 194 by one end and a transverse bore 196 of a needle valve 197 at the other end, the conical valve surface 198 having a vertex b of 40 , which is smaller than the vertex of 45" of the conical surface 199 of the seat 191.

The inlet valve 39 and the outlet valve 41 are arranged in a valve housing 43 to be accommodated in the pump housing 42. All valve housings 43 are in common enclosed in the pump housing 42 by means of a lid 100 with the interposition of a layer of elastic material 101.

Into each pump housing 42 is pressed with close fit a hard-steel cylinder 59. The pump housings 42 are located pairwise coaxially opposite one another and the front faces 60 of the housings 42 are spaced apart by a distance t by means of set pins 61, removed after mounting, and by tapped sleeves 62 rigidly securing the pump housings 42 to the frame plate 3 with or without the interposition of heat-insulating narrow strips 183, which define therebetween an air layer 184 between the frame plate 3 and the pump housings 42 in order to reduce the heat transfer from the electro-magnets 2 via the frame plate 3 to the pump housings 42. The tapped sleeves 62 constitute at the same time the connecting nipples for the fuel feed lines 107 connected with a fuel feeding pump 40 and for the fuel return conduits 109 leading via a pressure control-valve 152 to a tank 99, said return conduits being connected with a return outlet line 108. Each return conduit 109 communicates through a high-level channel 110 and a downwardly inclined channel 153 with the fuel inlet 27 of the two valve housings 43. Thus the fuel circulates at a high rate through the device 1 so that the fuel is not excessively heated in the device 1. It is, therefore, even possible to mount the device 1 at a fairly hot place, for example, directly on the engine 31. Any fuel vapour bubbles developing when the engine 31 and hence the fuel feeding pump 40 are standing still, will rise from beneath each valve housing 43 through the respective channel 153.

In each of the two pump housings 42 a venting screw 98 common to two pump chambers 29 seals a venting channel 97 opening out at the top of the pump housings 42 so that the emerging fuel is collected in a leakage fuel collector 96. The venting channel 97 communicates with the pump chambers 29 through inclined channels 94. The venting screw 98 is covered by a screw 95.

The displacer bodies 22 are made from a synthetic resin, preferably superpolyamide and comprise each a cup-shaped piston 63, a guide collar 64 engaging the pump chamber 29 and an axially extending, elastically deformable piston rod 65, whose end is fastened with the interposition of glue 91 in a bore 93 of a guide member 90 of a hard-steel coupling member 20. Owing to the clearance between the piston rod 65 and the bore 93 the piston 63 with the guide collar 64 is displaceable in a radial direction with respect to the guide member 90.

The displacer body 22 is manufactured by a method which will become clear from Figure 9, in which an injection moulding 54 of a synthetic resin, for example, polyamide is made in a mould 70, the cavity 71 of which is overdimensioned as compared with the final shape of the piston 63 indicated by broken lines 83. First a metal sleeve 74 is placed at the area of the piston rod 65 in the mould 70, the lid 75 having been removed. After the mould 70 is closed, synthetic resin is injected by means of an injection nozzle 76 into the cavity 71, the material thus settling around a collar 81 of the sleeve 74.After the removal from the mould 70 the piston 63 and the guide collar 64 are machined, particularly on the turner's lathe, to the prescribed size so that the cup-shaped sealing edge of the piston 63 and the guide collar 64 will have a satisfactory crystalline structure of high resistance to wear. During the machining operation the displacer body 22 is held with its metal sleeve 74 in a rotating clamp.

The valves 39 and 41 are manufactured in a similar manner to the displacer bodies and as shown in Figure 10. An injection moulding 154 of a synthetic resin, for example, polyamide, is made in a mould 156, whose cavity 157 is overdimensioned as compared with the final shape of the valves 39 and 41 indicated by the broken lines 158. After the injection into the cavity 157 and after the removal of the moulding 154 from the mould 156 the valves 39 and 41 are turned off to the prescribed size, so that a sealing edge 159, Figure 7, of satisfactory material structure and hence of high resistance to wear is obtained.

The device 1 comprises two coupling members 20 and the displacer bodies 22 of each pair of fuel pumps 32 are coupled with one another by means of one of the coupling members 20.

Each coupling member 20 is connected through an elastic coupling member 66 with an armature 18. The displacement volume of each fuel injection pump 32 is determined by the stroke of the coupling member 20, which will reciprocate so that a part spherical arm 79 thereon moves between the wedges 26 and 33.

The housings 69 each comprise two contiguous pump housings 42, between which wedges 26 and 33 are disposed as common stroke adjusting means for each of the pumps 32. A satisfactory seal of the piston 63 is obtained, since the guide member 90 guided in the cylinder 59 absorbs the tilting forces produced when the arm 79 strikes a wedge 26 or 33 at a point to one side of the axis 85 of the cylinder 59.

Attention is directed to the later description of Figures 15-25 for details of how the pumping chambers are provided in a bridge piece extending between two opposed housings 42, this feature having been omitted from the description of Figures 1-8.

As seen in Figure 4, the wedge 26 is driven by a piston 80 of a control-cylinder 73 communicating downstream from an air inlet valve 113 with the air inlet manifold 72 of the combustion engine 31, said cylinder being secured by clamps 119 to the frame plate 3.

Outside the control-cylinder 73, at the end remote from the wedge 26, an axially displaceable switch 82 is actuated when contacted by a cup member 166 of the piston 80. The switch 82 disconnects the pumps 32, when the pressure in the inlet manifold 72 drops below a given value. A reset spring 167 bears via the cup 166 and a ball 168 held therein on the piston 80, whose spherical surface 169 is in contact with the inner wall 115 of the cylinder 73. In this way a short cylinder 73 with low frictional resistance is obtained. The switch 82 preferably has known make-and-break contacts connected, as shown in Fig. 11, by means of a circuitry 160 to the terminals K, and K2 of each circuit 170 of Fig. 6. The circuitry 160 comprises three resistors 171, a transistor 172 and a relay 173.In order to avoid mechanical overload of the switch 82. it is actuated by the piston 80 through an abutting member 175 arranged beneath the cup 166 and resiliently held by a spring 174. The wedge 33 is coupled with barometer bellows 176, coupled in turn with a temperature sensor or feeler 178 affected by the engine temperature. For this purpose the lower end of the barometer bellows 176 bears on a rod fastened to the wedge 33. In the case of a low barometric pressure and/or of a high engine temperature sensed by the feeler 178 and taken by the silicon filled cylinder 177, the wedge 33 is urged down for reducing the quantity of fuel.In order to maintain a low frictional resistance and to obtain compact stroke control means, the piston 179 of the silicon filled cylinder 177 is hollow and has a hat-like bottom 182 for holding a slack compression spring 180, which is strongly biassed and which urges the piston 179 upwardly with respect to the wedge 33, whilst the bottom 181 of the barometer bellows 176 also having the shape of a hat, surrounds with ample clearance the hat-like bottom 182 and the piston 179 fits with ample clearance in the cylinder 177. With this construction the wedge-shaped stop 33 responds to slight pressure variations.

Each electro-magnet 2 is energized by means of a circuitry 170 shown in Fig. 6. An input K3 receives a control-pulse from a pulse generator 34, which is coupled with a cam shaft 163 of the engine 31. The pulse generator 34 comprises a rotary contact 155, which sequentially contacts one of the four contacts 16 for the sequential energization of the electro-magnets 2.

Each of these four contacts 16 is connected to an input terminal K3 of one of four circuits 170.

In this way the fuel required for each cylinder is injected by an atomizer 30 at the required instant of each cycle of the combustion engine 31. The sequence of energization of the electro-magnets 2 is chosen so that each of the wedges 26 and 33 is transiently set free of a coupling member 20 during each cycle so that they can be displaced each by slight forces. The switch 82 is included between the battery 35 and the contact 155 so that, when the switch 82 is switched off, no control-pulses are provided.

The device 201 shown in Figs. 12 to 14 for the delivery of fuel to eight atomizers 230 of an eight-cylinder combustion engine 231 is essentially a duplication cf the device 1, two devices 1 being mounted on a common frame plate 203.

Above each quadrant 238 of the common frame plate 203 an armature 218 extends transversely of the frame plate 203 between two alternately energized electro-magnets 202 and is connected with a coupling member 220, which extends near the central longitudinal plane 237 of the frame plate 203 in the direction of length thereof, said coupling member 220 having at each end a piston 222 limiting one of eight pump chambers 229. In the central longitudinal plane 237 a pump housing set 224 having four pump chambers 229 is arranged at the centre and two pump housing sets 269 having two pump chambers 229 are arranged at the ends of the frame plate 203. Four wedge-shaped stops 26 are disposed in the central longitudinal plane 237.

As illustrated in Fig. 14, each atomizer 230 injects fuel directly into a compression-loaded combustion chamber 225 so that in all combustion cylinders 217 the injection takes place at the same instant of the combustion cycle. Since the instant of the initial movement of each armature 218 depends upon the distance e between the armature 218 and the energized electro-magnet 202, it is important for all armatures 218 to be at the same distance e at the start of each stroke. For this purpose the four wedge-shaped stops 26 are displaced in an identical way in order for the curved arms 79 of the armatures 218 to reciprocate symmetrically to the central longitudinal plane 211 of each gap between two co-operating electromagnets 202.

Fig. 13 shows the four stops 26, which are coupled through adjustable fastening members 213, flexible members 212 and a rotatably journalled, common control-roller 208 with a regulating member, for example, an accelerator 207, if necessary, through a Bowden cable 219. Compression springs 209 hold the flexible members 212 in the taut state.

When fuel is injected into the compression-loaded combustion chambers 225, for example, at a pressure of 17 ato., the needle valve 397 should close at high pressure by means of a strong tensile spring 395. The needle valve 397 settles vibrating on its hard-steel seat 389, which is accompanied by shock waves in the fuel delivery conduits 228. Therefore, the pressure prevailing in the fuel delivery conduits 228 after the closure of the needle valves 397 is not always of the same value, which results in a varying fuel volume in these fuel delivery conduits 228 and hence in a non-uniform quantity of fuel per injection.

An improved uniformity of the fuel quantity per injection can be obtained by including in each rigid metal fuel delivery conduit 228 a length of hose 251 of a synthetic resin, particularly polyamide, and preferably located near each fuel pump 32. The hoses 251 preferably have equal lengths 1 of the order of 20 cms and an inner and outer diameter of the order of 2 mms and 4 mms respectively. Owing to the hose 251 the flow of fuel is slightly reduced, which results in an improved reproduceability of the fuel delivery.

The device of Figs. 15 to 25 corresponds with that of Figs. 1 to 11 and shows in detail the way in which opposed pumping chambers are provided in a bridge piece.

In order to ensure accurate alignment of the cylinder bores of the pairwise coaxially opposite fuel pumps 32, hard steel cylinders 59 are arranged in coaxial, short bores 400 of a U-shaped bridge piece 401. The manufacture and mounting operation are carried out in the stages illustrated in Figs. 21 to 24. In a metal body 402 is first made and broached a long, uninterrupted bore 403. Then a recess 404 is milled out to obtain a U-shaped bridge piece 401 with two separate, accurately aligned, short bores 400. Subsequently the coupling member 20 is placed in the bridge piece 401. The cylinders 59 fitting with forced fit in the bores 400 are slipped in said bores 400 and around the guide arms 405 of the coupling member 20 previously coated with adhesive sold under the Registered Trade Mark Araldite.

The guide arms 405 engage the cylinders 59 with sliding fit, so that the coupling member 20 is accurately orientated. Each piston 63 has a piston rod 65 and a cavity 406, the passage of which decreases towards the inlet 407. Into this cavity 406 is introduced an excess quantity of liquid adhesive, after which the piston 63 with the piston rod 65 is inserted into a narrowed bore 408 of a guide arm 405, the excess adhesive passing through a passage 404 into the bore 410 of the coupling member 20 whilst the piston rod 65 is glued to the coupling member 20 by the adhesive. The adhesive in the conical cavity 406 when hardened anchors the piston rod 65 on the guide arm 405. The bore 410 is honed and with the interposition of an elastic coupling 66 the coupling member 20 is secured by means of a pin 424 to an armature 18.Only then is the bridge piece 401 glued to the pump housings 42 by glue 438, for example, Araldite (Registered Trade Mark). Said pump housings 42 are bolted to the mounting plate 3. Since owing to the use of the bridge piece 401 the relative positions of the pump housings 42 are not important, the pump housings 42 can simply be secured to the frame plate 3 and may be made at low cost, for example by injection moulding of a synthetic resin.

In each pump housing 42 various channels are bored. Behind the bores 411 for valve housings 43 and through the high-level channel 110 are drilled vertical channels 412, receiving non-tapped nipples. The bores 412 and 411 communicate with one another through horizontal channels 414. After the insertion of the nipples, the inputs of the channels 110 and 414 are closed by plugs 415 of hardening material, for example, Araldite (Registered Trade Mark). These plugs 415 safeguard the fixation of the nipples.

As seen in Figure 18, a reset spring 167 bears on the piston 80 via the cup member 166 and a ball 168 held therein and formed by a nut screwed to the end of the rod of the wedge 26. The piston 80 seals with the inner wall 115 of the cylinder 73 through two axially spaced sliding rings 416 of a polyamide material produced by polycondensation of omega-aminoundecanoic acid and sold under the Registered Trade Mark Rilsan. The spring 167 bears furthermore via a dish 421 on a ball-shaped end 422 of the housing of the switch 82 held therein. In this way a short cylinder 73 with low frictional resistance is obtained. In order to avoid mechanical overload of the switch 82, the switch bears via a spring on a collar 418 of a cover 419. The switch 82 is axially displaceable by screw thread 420 in the cylinder 73 so that the length and hence the bias tension of the spring 167 can be adjusted.Therefore, the spring 167 need not have an accurately predetermined length and any spring having the required spring constant will suffice.

The wedge 33 is coupled with a barometer bellows 176. Inside the bellows 176 the prevailing pressure is not more than 5 mms Hg. Therefore, the influence of the temperature variation on the adjustment of the wedge 33 is slight. The spring 425 acting against the bellows 176 must have a high bias tension, i.e. 600 mms Hg, whilst the path of the wedge 33 amounting, for example, to 6 mms has to be covered at a pressure varying between 600 and 760 mms Hg. The bellows 176 are soldered to the bottom 426 of a hollow piston 427, which is slidable in a cylinder 429 by axially spaced sliding rings of Rilsan (Registered Trade Mark).

After evacuation of the bellows 176 to 5 mms Hg, the suction nipple 430 is closed by soldering. It is covered by a cap 431 having a screw thread 432, which co-operates with a cup member 433 for the adjustment of the length of the spring 425. Then a cover 434 is screwed onto the cap 431 which is held against rotation by means of a screw driver inserted into a slot 435, guide pins 436 then being passed through the cover 434 into the dish 433 as well as a nipple 437. The cylinder 429 is fastened, for example, by means of Araldite (Registered Trade Mark) to the cover 100 only after the wedge 33 is in its place. Thus the wedge eccentrically engaging the bottom 426 can exert an axial force on the piston 427 without deflecting. The spring 425 surrounding the bellows 176 has a large diameter and hence it is stable.

The quantity of fuel at idling speed can be adjusted by turning the cap 431 by means of a screw driver inserted into the slot 435.

The barometer bellows 176 are arranged in a barometer housing formed by the cylinder 429, communicating with the air inlet manifold 72 of the combustion engine 31 through a choke valve 439, which can be manually opened when starting the combustion engine 31 in the cold state.

According to the connecting diagram of Fig. 26, an air chamber 440 communicates through a non-return valve 441 with the air inlet manifold 72 and through a choke valve 439 with a nipple 456, said valve 439 being automatically actuated by a control-member 442 subjected to a thermostat 443 responsive to the temperature of the combustion engine 31. Parallel to the choke valve 439 a valve 445 connects the barometer housing 429 via the air chamber 440 with the air inlet manifold 72.The valve 445 is subjected to a feeler 446 responding to the composition of the exhaust gases of the combustion engine 31 in the exhaust 444, the measured CO- and/ or O2 content being compared with a value adjusted in a comparator 447 so that the valve 445 is opened when the measured CO content is equal to, for example, 3%, whereas it is closed when the measured CO-content is equal to 1%. In this way the air/fuel mixture fed to the combustion cylinders of the combustion engine 31 is prevented from becoming too rich for a complete combustion of the fuel.

The 6-cylinder combustion engine 31 shown in Fig. 27 is fed by means of an injection device substantially corresponding to the preceding Figures, but having not more than four pump chambers 29. This is rendered possible by six valves 448(1), 448(2), 448(3), 448(4), 448 5) and 448(6) associated with the atomizers 30 injecting fuel into the branches 428 of the air inlet manifold 72 and being associated with the combustion cylinders 17(1), 17(2), 17(3), 17(4), 17(5) and 17(6) respectively.With a conventional sequence of ignition: 1,5,3,6,2,4 the valves 448 are opened in said sequence during the inlet strokes of the respective combustion cylinders 17 since a pulse generator 455 arranged on the cam shaft 163 and co-operating with coils 449(1), 449(5), 449(3), 449(6), 449(2) and 449(4) respectively delivers pulses via a circuit 450 for energizing the valves 448, which are opened when required for the instant when one of the four fuel pumps 32 starts delivering fuel, whilst the period of opening is adjusted at such a value that the values 448 close only after a fuel pump 32 has pumped the full quantity required and has thus taken place a complete injection of fuel.

A pulse generator 451, which may be driven through a gear wheel transmission 452 having a ratio of 3 : 2 by the cam shaft 163, and co-operating with coils 453(1), 453(2), 453(3) and 453(4) and a circuit 454, delivers pulses to four circuits 170 of the pumps 32(1), 32(2), 32(3) and 32(4).

The chronological diagram is then as follows: Ignition Valve Position of sequence lift Pump sequence cam shaft 1 448(1) 32(1) 0" 5 448 5 32(2 60 3 448(31 32 3 1200 6 448(6) 32 1 1800 2 448(2) 32(1) 240 4 448(4) 32(2) 300 1 448() 32(3) 0 5 4485 32(4) 60 3 448(3) 32(1) 1200 6 448(6) 32(2) 1800 2 448(2) 32(3) 240 4 448(4) 32(4) 300 As a matter of course a 4-cylinder fuel injection pump can in this way feed any combustion engine, for example, a 3-, 5-, 7- or 8-cylinder combustion engine.

Hereunder will follow a description of the device of Figures 28 to 36.

For details of how the pumping chambers are provided in a bridge piece between two opposed housings 42 in the device of Figures 28 to 36 reference is made to the preceding description of Figures 15 to 25.

The device 1 comprises a cast or spray-cast aluminium frame 3. Magnet plates 5 are stacked up in a jig and interconnected at their outer edged by glue 7. Two pairs of electro-magnets 2 are firmly secured by means of bolts 6 between the frame 3 and a lid 4. Each of the electro-magnets 2 comprises a core 10 formed by a packet of magnet plates 5 and an energizing coil 14 surrounding said core 10. Beneath each electro-magnet 2 the frame 3 has a wide air passage 8 allowing air to pass for cooling the electro-magnets 2. A plate-shaped armature 18 is adapted to reciprocate between each pair of alternately energized magnets 2.

Each armature 18 is pivoted by an end 9 in a slot 13 of a bearing element 11 of synthetic resin, preferably polyethylene terephthalate as sold under the Registered Trade Mark Arnite, embedded in a bearing block 12, which is integral with the frame 3.

At the free end 15 each armature 18 holds a cross-shaped coupling member 20, with which are connected two displacer bodies 22 of two fuel pumps 32. The stroke of the displacer bodies 22 is determined by adjustable stroke adjusting means arranged on either side of the coupling members 20 and formed by two wedges 26 and 33. Each pump 32 comprises a pump chamber 29 accommodated in a pump housing 42 and having a fuel inlet 27 and a fuel outlet 28, each of the outlets leading to an atomizer 30 of a combustion engine 31. The inlet valve 39 and the outlet valve 41 are arranged in a separate valve housing 43, to be arranged in the housing 42, said valve housing comprising three parts to be interconnected i.e. an inlet seat 44, a tube 45 secured to the former by cement 160 and an outlet seat 46 secured in place in said tube 45 by cement 17. The inlet seat 44 to be connected with a fuel supply pump 40 has at its entrance a filter 49 of filter gauze and an annulargroove 19 receiving a seal 50 for isolation from the pump housing 42. The tube 45 has an external annular groove 51 and a channel 52, through which the space 53 of the valve housing 43 between the inlet valve 39 and the outlet valve 41 communicates with the pump chamber 29. The tube 45 has a further annular groove 55 receiving a seal 56. All valve housings 43 are simultaneously enclosed in the pump housing 42 by means of a lid 100 with the interposition of a layer of elastic material 101.In order to avoid penetration of dirt into the valve housing 43, particularly when the valve housing 43 as a unit is still located outside the pump housing 42, the fuel inlet 27 as well as each fuel outlet is provided with a filter. For example, a cylindrical filter 102 of filter gauze is arranged in the groove 51 and a filter 103 of filter gauze is enclosed in the fuel outlet 104 with the aid of a valve stop 105, which limits the maximum lift of the outlet valve 41 and which is formed by a sleeve having radial recesses 106. The inlet valve 39 and the outlet valve 41 comprise each a valve body 78 of a synthetic resin and a copper supporting ring 57 for a valve spring 58.

Into each pump housing 42 is pressed a hard steel cylinder 59 with close forced fit. The pump housings 42 are pairwise arranged coaxially opposite one another and spaced apart from one another by their front faces 60 by a distance t. Connecting members secure the housings 42 in place and are formed by fitting pins 61 and threaded sleeves 62, rigidly connecting the pump housings 42 with the frame 3. The front faces 60 are accurately held in relatively parallel positions by means of the fitting pins 61. The sleeves 62 constitute in addition the connecting nipples for the fuel supply conduits 107 and the fuel return conduits 108, the latter leading to the tank 99 via a return outlet and a pressure control-valve 152. The return outlet 109 communicates through a channel 110 of the pump chambers 29 with the fuel inlet 27.Thus the fuel circulates at a high rate through the device 1 so that the fuel is not excessively heated in the device 1. It is therefore possible to mount the device 1 at a fairly hot place, for example, directly on the combustion engine 31. In each of the two pump housings 42 a vent screw 98 common to two pump chambers 29 seals a vent channel 97, which opens out at the top of the pump housings 42 so that the emerging fuel is collected in a fuel leak collecting space 96. The vent channel 97 communicates with the pump chambers 29 through inclined channels 94. The vent screw 98 is covered by a screw 95.

The displacer bodies 22 are each made of a synthetic resin, preferably a superpolyamide and are each formed by a cup-shaped piston 63, a guide collar 64 engaging the pump chamber 29 and an axially extending, elastically deformable tie member 65, whose end 92 is secured with the interposition of glue 91 in a bore 93 of a guide member 90 of the respective hard steel coupling member 20. Owing to the clearance between the tie member 65 and the bore 93 the piston 63 with the guide collar 64 is displaceable in a radial direction with respect to the guide member 90. The device 1 comprises two cross-shaped coupling members 20 by which the displacer bodies 22 of each pair of fuel pumps 32 are coupled with one another. Each coupling member 20 is connected by means of an elastic coupling 66 to a respective armature 18.This elastic coupling 66 comprises an elastic ring 67, accommodated in the coupling member 20 and surrounding a pin 68 of the armature 18 and preferably made of a superpolyamide.

The displaced volume of each fuel pump 32 is determined by the stroke of the coupling member 20, which is adapted to reciprocate so that a part-spherical arm 79 thereon moves between the wedges 26 and 33. In order to obtain an accurate adjustment of said stroke both the coupling member 20 and the wedges 26 and 33 are made of hard steel, whilst the wedges 26 and 33 accommodated each in a guide groove 89 in a pump housing 42 are in engagement with a pump housing 42 with the interposition of the supporting layer 88 of a synthetic resin, preferably polyethylene terephthalate. In order to avoid excessive wear of these parts the comparatively small overall bulk of the coupling member 20 and the two displacer bodies 22 connected with the former is separated from the comparatively large bulk of the armature 18 by using the elastic coupling 66.At each stroke the coupling member 20 butts against a comparatively hard stop, whilst the bulk of the armature 18 continues to move over a small distance and is arrested resiliently.

Two housing blocks 69 comprise each two joined pump housings 42, between which wedges 26 and 33 are arranged to serve as common control-means for each of the pumps 32.

The distance t and the coupling members 20 are particularly small since the wedges 26 and 33 are held in guide grooves 89 of the pump housings 42 so that inaccuracies of the fuel displacements due to deformation of coupling members and/or to mounting defects are slight. A satisfactory seal of the piston 63 is obtained since the guide member 90 guided in the cylinder 59 absorbs the tilting forces produced when the arm 79 forming a stop member strikes a wedge 26 or 33 to one side of the axis 85 of the cylinder 59. In order to ensure a long lifetime of the device 1 each guide member 90 is coated with a wear-resistant material 87, preferably Polyamide sold under the Registered Trade Mark Rilsan, which is applied by dipping and subsequently machined to the prescribed size.

In the unmounted state illustrated in Fig. 35 the sealing rim 86 of the piston 63 projects radially beyond the guide collar 64. The sealing rim 86 is sharp so that in the mounted state it assumes the satisfactorily sealing form shown in Fig. 34 and has a long lifetime, particularly if the cylinder 59 is formed by a silver steel sleeve.

The armature 18 engages an adjustable setting member extending at right angles to the direction of movement of said armature 18 and being formed by a set screw 84, Figure 30.

The armature 18 is adapted to pivot about the axis 85 of the cylinder 59. Thus during assembly of the armature it is turned about said axis 85 so that its end 9 enters the open upper end of slot 13 in the bearing element 11 and is received between the set screw 84 and a spring 111 located in a recess 112, the armature 18 being subsequently urged against the set screw 84, which closes the slot 13. By means of the set screw 84 the angular position of the armature 18 about the axis 85 is adjusted and hence also the point of engagement of the ball-shaped arm 79 on the stop faces of the wedges 26 and 33 extending obliquely to the oscillatory movement of the armature 18.

The wedge 26 is driven by a piston 80 of a control-cylinder 73 communicating downstream of an air inlet valve 113 with the air inlet manifold 72 of a combustion engine 31. The control-cylinder 73, the length of which is held at a minimum, is centered with respect to the frame 3 by means of a centering disc 114, which extends into the bore 115 of the controlcylinder 73 and in a centering hole 116 of the frame 3. The control-cylinder 73 is adapted to turn about the centering disc 114 and to be fixed in the desired position by clamping means formed by clamping screws 117 and clamps 119 engaging an external groove 118 of the control-cylinder 73.The top side of the control-cylinder 73 communicates through recesses 121 in the centering disc 114 and recesses 122 in the frame 3 with a fuel leak collecting space 96 so that any leakage can flow via the outer side of the piston 80 and the control-cylinder 73 towards the inlet manifold 72. In order to maintain the cleanness of the control-cylinder 73 a filter of filter gauze is arranged between the centering disc 114 and the frame 3. Externally of the control-cylinder 73, at the end remote from the wedge 26, an axially displaceable switch 82 is controlled by an extension 124 of the piston 80 for stopping the pumps 32 in the event of a drop beneath a given pressure in the inlet manifold 72. The switch 82 can be readily actuated.

A control-rod 126 extending axially across a wide bore 125 of the wedge 26 and being rigidly secured to the piston 80 is adapted to turn with respect to the wedge 26. Owing to the clearance between the bore 125 and the control-rod 126 and to the relative rotatabilityofthe wedge 26 and of the control-rod 126 the high-frequency vigourous impacts of the armature 18 are hardly or not at all transferred to the piston 80.

The wedge 33 is adjustable in accordance with the engine speed. A screw rod 127 extending across the wedge 33 is adapted to turn with an amount of clearance and to be displaced in a transverse direction with respect to the wedge 33, which is urged by a spring 128 against a shoulder 129 of the screw rod 127. The top end of the screw rod 127 has a screwthread 130 engaging a screwthread piece 131 of a metal bellows barometer 133. After evacuation the bellows 133 is closed by a nipple 132. The top end of the bellows 133 supports a diaphragm 134 of a pressure chamber 135, which communicates through a choke 136 with the inlet manifold 72. The pressure chamber 135 has an air inlet 138 controlled by an air valve 137. The air valve 137 is closed by an electro-magnet 139, which is energized in accordance with the speed of the combustion engine 31.The electro-magnet 139 is each time energized upon the energization of an electro-magnet 2. If the speed of the combustion engine 31 is high, the air valve 137 remains closed so that a high vacuum is produced in the pressure chamber 135, as a result of which the quantity of fuel supplied is increased. Likewise the quantity of supplied fuel increases if the barometric air pressure is high. In both cases the wedge 33 is lifted.

The pressure chamber 135 comprises a control-member formed by the diaphragm 134, which is adjustably connected with the wedge 33, since the pressure chamber 135 together with the diaphragm 134 and the barometer bellows 133 is adapted to turn with respect to the screw rod 127. Since the head 140 of the screw 127 is prevented from turning in the guide groove 89, the starting position of the wedge 33 can be adjusted in an axial direction. After the adjustment the pressure chamber 135 is anchored by means of a safety pin 141 with respect to a holder 142.

Between the pump housings 42 and the hot electro-magnets 2 air gaps 144 are provided for heat insulation. These gaps 144 are covered by elastic strips 145 to prevent penetration of dirt.

Each electro-magnet 2 is controlled by a circuitry 170.

In the variant shown in Figure 36 the set screw 146 is disposed outside of the bearing element 11 on the bottom side of the armature 18, whereas the spring 111 is arranged on the top side.

Attention is directed to the complete specifications of our copending Applications 7905026 (Serial No. 1575233) and 7905028 (Serial No. 1575234), the claims of which protect fuel supply devices and systems as described herein above.

Claims

WHAT WE CLAIM IS:

1. A device for delivering fuel to a combustion engine, comprising at least one pair of fuel pumps, each fuel pump including a pumping chamber and passages communicating the chamber through an inlet valve with a fuel supply and through an outlet valve with a fuel delivery port to be connected with the combustion engine, each said pumping chamber being variable in volume by a reciprocable displacer body, the displacer bodies of the or each pair of fuel pumps and driving means therefor being intercoupled by means of a coupling member arranged between the two fuel pumps, and wherein the pumping chambers of the or each pair of fuel pumps are provided in a bridge piece comprising two opposed ends interconnected by an intermediate piece, said chambers being bounded within coaxial bores located one in each end of the bridge piece.

2. A device as claimed in claim 1, wherein the pump chambers are bounded by hard steel cylinders arranged in the coaxial bores of the bridge piece.

3. A method of manufacturing a device as claimed in claim 1 or 2, wherein the bridge piece is made in a body of rigid material by making and broaching a long bore, which is subsequently divided into two coaxial, relatively spaced short bores by milling out material to form a recess between them.

4. A method as claimed in claim 3, wherein the coupling member is arranged in the recess thus made, after which into each bore is slipped a fitting, hard-steel cylinder with sliding fit around one of two guide arms of the coupling member.

5. A method as claimed in claim 3 or 4, wherein each displacer body formed by a piston is fastened to a guide arm of the coupling member after the two guide arms of the coupling member have been mounted with sliding fit in the respective bore.

6. A method as claimed in claim 5, wherein the piston is glued to the guide arm of the coupling member.

7. A method as claimed in claim 6, wherein the piston is fixed to a guide arm of the coupling member by means of adhesive.

8. A method as claimed in claim 5 or 6, wherein the piston is glued to a guide arm of the coupling member by means of liquid material, which is introduced into a cavity of a piston rod of the piston, said cavity having a passage diminishing towards its entry.

9. A method as claimed in anyone of claims 3 to 8, wherein the bridge piece is fastened in pump housings not until after the displacer bodies and their coupling member have been reciprocably mounted in the coaxial bores.

10. A device as claimed in claim 1 or 2, in which each pump chamber has a displacement volume adjustable by control means which are coupled with a barometer bellows, wherein the barometer bellows have an internal pressure substantially lower than the atmospheric pressure.

11. A device as claimed in claim 10, wherein the pressure prevailing in the barometer bellows is the order of 5 mms Hg.

12. A device as claimed in claim 10 or 11, wherein the barometer bellows co-operates with a spring whose bias tension corresponds to about 600 mms Hg.

13. A device as claimed in claim 10, 11 or 12, wherein the barometer bellows co-operates with a spring engaging an axially displaceable cup member.

14. A device as claimed in any one of claims 10 to 13, wherein the barometer bellows are arranged in a barometer housing communicating, in use, through at least one valve with the air inlet manifold of the combustion engine.

15. A device as claimed in claim 14, including a choke valve and wherein the barometer housing communicates, in use, through the choke valve with the air inlet manifold of the combustion engine.

16. A device as claimed in claim 14 or 15, wherein the barometer housing communicates with the air inlet manifold through a valve controlled by means sensitive to the composition of the exhaust gases of the combustion engine.

17. A device as claimed in claim 14, 15 or 16, wherein the barometer housing communicates with the air inlet manifold not only through said valve but also through an air chamber with a non-return valve.

18. A device as claimed in claims 1, 2 or 10 to 17, wherein each fuel pump is mounted on a common frame plate with the interposition of heat-insulating material.

19. A device as claimed in claims 1,2 or 10 to 18, wherein the pump chambers of eight fuel pumps each have a displacement volume adjustable by control means comprising a plurality of wedge-shaped stops for the displacer bodies each of the stops being actuated by a control-member, wherein the control-member is coupled with each of the wedge-shaped stops through a common, rotatably journalled control-roller and a plurality of flexible members coupling said roller with the stops.

20. A device as claimed in claim 19, wherein above each quadrant of a common frame plate an armature extends transversely of the frame plate between two electro-magnets and is connected with a coupling member, which extends near and parallel to the central longitudinal plane of the frame plate and which is provided at each side with a piston, which limits one of said pump chambers.

21. A device as claimed in claim 20, wherein in the central longitudinal plane a pump set comprising four pump chambers is arranged at the centre of the frame plate and two pump sets comprising each two pump chambers are arranged at the respective ends of the frame plate.

22. A device as claimed in claim 20 or 21, wherein the wedge-shaped stops are disposed in the central longitudinal plane.

23. A device as claimed in claims 1, 2 or 10 to 22, in which the pump chamber of each fuel pump has a displacement volume adjustable by control means comprising an air cylinder to be connected with the inlet manifold of the combustion engine, a piston of which cylinder moves against the action of a compression spring, wherein the compression spring loads the piston via the edge of a cup member and a ball included in said cup member.

24. A device as claimed in claim 10 or any one of claims 11 to 23 when dependent upon claim 10, wherein the barometer bellows are coupled with a temperature sensor responsive to the engine temperature.

25. A device as claimed in claim 24, wherein the barometer bellows are incorporated in a piston of a cylinder of the temperature sensor.

26. A device as claimed in any one of claims 1,2 or 10 to 18 wherein stroke control means are provided for the displacer bodies and comprise two rigidly interconnected, wedge-shaped stops limiting the reciprocatory stroke of the displacer bodies.

27. A device as claimed in claims 1, 2 or 10 to 26, wherein each displacer body consists of a piston which is radially displaceable with respect to a guide member guided in a bore of the pump.

28. A device as claimed in claim 27, wherein the piston is provided with an elastically deformable tie member connected with the guide member.

29. A device as claimed in claim 27 or 28, wherein the tie member extends axially in a bore of the guide member with a given amount of clearance.

30. A device as claimed in claim 27, 28 or 29, wherein the tie member comprises a guide collar guided in the bore of the pump between the piston and the guide member.

31. A device as claimed in anyone of claims 27 to 30, wherein the piston has the shape of a cup.

32. A device as claimed in claim 31, wherein the piston has a sharp sealing edge.

33. A device as claimed in claim 30, wherein in the unmounted state of the piston the sealing edge of the cup-shaped piston projects radially beyond the guide collar.

34. A device as claimed in anyone of claims 27 to 33, wherein the piston is made of a synthetic resin.

35. A device as claimed in claim 34, wherein the piston is made of superpolyamide.

36. A device as claimed in anyone of claims 27 to 35, wherein the guide member is coated with wear-resistant material.

37. A device as claimed in claim 36, wherein the guide member is coated with material applied thereto by dipping.

38. A device as claimed in claim 36 or 37, wherein the guide member is coated with a polyamide produced by polycondensation of omega-amino undeconoic acid.

39. A device as claimed in anyone of claims 27 to 38, wherein the guide member and the piston are arranged in a bore of a silver steel sleeve.

40. A device as claimed in anyone of claims 27 to 39, wherein the guide member forms part of a coupling member which comprises to one side of the axis of the bore of the pump chamber a stop member co-operating with a stop.

41. A device as claimed in claims 1, 2 or 10 to 40, wherein the or each driving means comprises a pivotably mounted armature movable by electro magnets, each fuel pump and each electro-magnet being secured to an aluminium frame.

42. A device as claimed in claim 41, wherein beneath each electro-magnet the frame has a wide air passage.

43. A device as claimed in claim 41 or 42, wherein a bearing block for the pivotable mounting of the or each armature is integral with the aluminium frame.

44. A device as claimed in claim 41,42 or 43, wherein the aluminium frame is a cast or a spray-cast.

45. A device as claimed in anyone of claims 1, 2 or 10 to 44, wherein the inlet and outlet valves of each fuel pump are arranged in a separate valve housing and in communication with the pump chamber, wherein the valve housing comprises at least two, but preferably three parts sealingly connected to one another.

46. A device as claimed in anyone of claims 1,2 or 10 to 45, wherein the inlet and outlet valves of each fuel pump are arranged in a separate valve housing and in communication with the pump chamber, wherein the valve housing is provided with a filter at each fuel inlet and each fuel outlet.

47. A device as claimed in claim 46, wherein each filter is formed by a mass of filter gauze.

48. A device as claimed in anyone of claims 1, 2 or 10 to 47, wherein each outlet valve is provided with a stop limiting the lift of the valve.

49. A device as claimed in claim 48, wherein the valve stop is formed by a sleeve having at least one radial recess.

50. A device as claimed in anyone of claims 1, 2 or 10 to 49, wherein each pump has an addition a return outlet which connects the pump chamber through a pressure control-valve with the fuel inlet.

51. A device as claimed in anyone of claims 1,2 or 10 to 50, wherein the inlet and outlet valves of each fuel pump are arranged in a separate valve housing, the valve housings having a common lid.

52. A device as claimed in claim 51, wherein a layer of elastic material underlies the lid.

53. A device as claimed in anyone of claims 1,2 or 10 to 18, in which each pump chamber has a displacement volume adjustable by control means, said control means comprising at least one wedge-shaped stop for the displacer bodies, the stop being actuated by a controlmember, wherein the wedge-shaped stop is held in a guide groove provided in a pump housing.

54. A device as claimed in anyone of claims 1,2 or 10 to 18, in which each pump chamber has a displacement volume adjustable by control means, said control means comprising at least one wedge-shaped stop for the displacer bodies, the stop being actuated by a controlmember, wherein a control-rod passing axially through the wedge-shaped stop is adapted to turn with respect to the wedge-shaped stop.

55. A device as claimed in anyone of claims 1,2 or 10 to 18 in which each pump chamber has a displacement volume adjustable by control means, said control means comprising at least one wedge-shaped stop for the displacer bodies, the stop being actuated by a controlmember, wherein the wedge-shaped stop is displaceable in a transverse direction with respect to a control-rod passing axially of the wedge-shaped stop.

56. A device as claimed in claim 54, or 55, wherein the stop is urged by a spring in an axial direction against a shoulder of the control-rod.

57. A device as claimed in anyone of claims 1,2 or 10 to 18, in which each pump chamber has a displacement volume adjustable by control means, said control means comprising at least one wedge-shaped stop for the displacer bodies, the stop being actuated by a controlmember, wherein the wedge-shaped stop bears on a pump housing through a supporting layer of a synthetic resin.

58. A device as claimed in claim 57, wherein said supporting layer is made of polyethylene terephthalate.

59. A device as claimed in anyone of claims 1,2 or 10 to 18, in which each pump chamber has a displacement volume adjustable by control means, comprising at least one wedgeshaped stop for the displacer bodies, the stop being actuated by a control-member, said stop being coupled through a piston rod with the piston of a control-cylinder to be communicated with the inlet manifold of the combustion engine, wherein the control-cylinder is centered with respect to a frame holding the or each bridge piece by means of a centering disc extending into the control-cylinder.

60. A device as claimed in claim 59, wherein the control-cylinder is adapted to turn about the centering disc and can be fastened to the frame by means of clamping members.

61. A device as claimed in claim 59 or 60, wherein the top side of the control-cylinder communicates through recesses in the centering disc and in the frame with a leaking fuel collecting space.

62. A device as claimed in claim 61, wherein a filter is arranged between the centerind disc and the frame.

63. A device as claimed in anyone of claims 1, 2 or 10 to 62, wherein the driving means comprise an armature energized by at least one electro-magnet and adapted to reciprocate between stops, wherein at least one of the stops is adjustable in accordance with the speed of the engine.

64. A device as claimed in claim 63, wherein the further stop is acted upon by a pressure chamber to be communicated through a choke with the inlet manifold of the combustion engine and having an air inlet controlled by an air valve, said air valve being electromagnetically closed by an electro-magnet energized in accordance with the speed of the combustion engine.

65. A device as claimed in claim 63 or 64, wherein the adjustable stop is furthermore subjected to the action of a barometer bellows.

66. A device as claimed in claim 64 or 65, wherein the adjustable stop has a screw rod which is adjustably connected with the control-member of the pressure chamber.

67. A device as claimed in claim 1, wherein the pump chamber of at least one fuel pump has a displacement volume adjustable by control means, comprising an air cylinder to be connected with the inlet manifold of the combustion engine, a piston of which cylinder moves against the action of a compression spring and actuates a switch for stopping the pump when the air pressure in the inlet manifold drops below a given value, wherein said switch comprises a make-and-break contact.

68. A device as claimed in claim 1, wherein the pump chamber of at least one fuel pump has a displacer volume adjustable by control-means, comprising at least one wedge-shaped stop for the displacer body or bodies, the stop being actuated by a control-member, said stop being coupled through a piston-rod with the piston of a control-cylinder to be connected with the inlet manifold of the combustion engine, wherein at the end of the control-cylinder remote from the stop an axially displaceable switch is provided for stopping the pump when the pressure drops below a given pressure in the inlet manifold.

69. A device as claimed in claim 1, wherein the pump chamber of at least one fuel pump has a displacer volume adjustable by control means, comprising an air cylinder to be connected with the inlet manifold of the combustion engine a piston of which cylinder moves against the action of a compression spring and actuates a switch for stopping the device, when the air pressure in the inlet manifold drops below a given value, wherein the switch is actuated by the piston of the air cylinder through a spring-loaded abutting member.