US 2258586 A
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Patented Oct. 14, 1941- ELECTROMAGNETICALLY OPERATED PETROL SUPPLY PUMP .Karl- Glissing, Stuttgart, Germany, assignor to Robert Bosch Gesellschaft mit beschrink'ter Hattung, Stuttgart, Germany Application March 22, 1939, Serial No. 263,574 In Germany April 9, 1938 7 Claims.
The invention relates to electromagnetically operated petrol supply pump of the type wherein a snapspring, which carries a contact, opens and closes the circuit dependently upon the armature movement.
In known fuel supply pumps of this typ the ends of the snap spring are disposed unyieldingly, so that in action the springbends into an S shape, and consequently the drive must be placed near one end of the spring, and the operating contact near the other end. This results in complexity of construction.
The object of the invention is to try to eliminate this disadvantage and to increase the life of the spring.
According to the invention, in an apparatus of the type set forth, the snap spring is mounted in a longitudinally resilient manner, and a contact is disposed substantially centrally of the spring through which contact the movement of said spring is influenced by means of a counter contact associated with th armature.
An example of construction in accordance with the invention is shown in the accompanying drawing:
Figure 1 shows a full length section along the line I-I of Figure 2.
Figure 2 a full length section along line II-II of Figure 8.
Figure 3 a partial cross-section along line IIIIII of Figure 1.
Figures 4 and 5 are sectional views of the device in two different working positions.
The roughly cylindrical component In. of the pump shell, which is closed at the top and provided with a threaded support I for connecting the fuel outlet pipe, is closed at the lower end by the component 2, which is held in position by the screw 3. The component 2 is provided with a threaded support 4, for holding the fuel inlet pipe, and a sieve 5. Between the shell components In and 2 are clamped a bed plate 6 and washers 'I. On the underside of the plate 6, which is bored through the middle, is disposed a valve seating 8 to take the inlet valve 9. A core I0, having a boring which widens towards the top, is seated on the plate 6 and has a ring-shaped shoulder I I on its inner periphery, on which a spring H0, is supported. The core III is surrounded by the non-magnetic brass guiding sleeve I2, around sulated from the sleeve) two plate springs I5,
each of which reaches above th sleeve, and one of which is connected through a spring contact II with a leading in terminal I6. Theupper ends of the springs I5 form the seating of the snap spring I8. This snap spring carries in the middle of its upper side a contact I9.
In the sleeve I2 there is a movable armature 20, constructed as a piston, which at its lower end tapers off downwards (23), and which is forced upwards by the spring Ila. The axially bored piston 20 has at its upper end a seating for the outlet valve 2I and an angular stirrup 22 which bends over the snap spring I8 and carries the counter-contact 22a for the contact IS. The counter-contact is insulated from the stirrup 22 and connected through a wire 22b with the coil I3. A lug 24 mounted on the end facing of the sleeve I4, which is closed at the top, limits the upward push of the piston 20. The shell component Ia which encloses the magnet coil consists, in cross-section of two arc-shaped cover pieces 25 joined together by two projecting pieces 26 (Figure 3). The parts 26 enclose the springs I5 and the means of fastening them to the sleeve I4. One of these shell parts 26 contains also the spring contact I1, which carries the current, and the end of the leading in terminal I6. The arc shaped shell parts 25 enclose the outer sleeve ll of the magnet coil, allowing a little play.
The operation of the pump is as follows:
In the rest position, the piston 20 is pressed by the spring IIa against the stop 24. Both valves 9 and 2I are closed. The snap spring I8 is defiected upwards, its contact I9 lying against its counter contact 22a. There is then a conducting contact from the terminal I6 through the springs I'I, I5, III and contact I9 to the counter-contact 22a, and from there through the wire 22b and the spool I3 to the mass of the casing. When the current is switched on the piston 20 is drawn into the spool I3 against the action of the spring Ho. The middle of the snap spring I8 with the contact I9 is pushed downwards by the contact 22a which descends with the piston 20. The snap spring new approaches its fully stretched position, as the plate springs acting as its seating bend outwards. At the same time, the valve 2I opens, and the fuel inside the piston passes into the casing Ia. When the piston has almost reached its lower stop position, i. e., the core III, which acts as a stop, the snap spring I8 is stretched out straight by the descending countercontact piece 22a (Figure 4). The next moment the spring I8, under the sideways pressure of the plate springs I5, snaps through into the downarmature through which said electromagnet system is energised, in combination with a snap spring mounted at its ends in a longitudinally resilient manner, and a second contact abuttable with the contact aforesaid and carried by the snap spring substantially centrally thereof by means of which second contact movements of the snap spring are influenced by the other contact borne by the displaceable armature.
6. An apparatus according to claim 4, in which there is a terminal contact piece supported by said shell and a terminal contact spring attached to one of said plate springs and arranged to resiliently abut the aforesaid terminal contact piece, and in which the shell is provided with projecting wall parts which provide laterally extending recesses to enclose said plate springs.
7. In a fuel pump, an electromagnet, an armature displaceable by said electromagnet, a contact carried by said armature, a flat snap spring, means for resiliently supporting said snap spring at its ends to yieldingly permit longitudinal movement of said ends, said armature being formed to provide a reciprocable pump piston mounted between said resilient supporting means, and a second contact carried by said snap spring substantially centrally thereof and adapted to be engaged and moved by said firstmentioned contact to control a circuit through said electromagnet, said armature carrying means including said first-mentioned contact adapted to'engage alternately opposite sides of said spring whereby said spring is engaged and moved in one direction by direct engagement of the armature with said spring and moved in the other direction by said armature through the contact carried thereby.
Oct. 14, 1941. I w c GRABAU 2,258,607
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