Crashworthy fuel pump

A crashworthy fuel pump has a body in which is formed a fuel intake cavity, a fuel discharge cavity, and a fuel pumping chamber. The body has an open end around the periphery of which is formed a lip. A flexible diaphragm is insertable into the open end of the body and the lip is bendable over the outer margin of the diaphragm to clamp the diaphragm within the body. A housing has one end formed for abutment with the open end portion of the body. The body and the housing are clamped together to form a unified assembly. The clamp is sufficiently strong to hold the assembly together when the assembly is subjected to normal forces, but breaks apart when the assembly is subjected to abnormal forces such as occur during a crash whereby the housing and the body can move apart from each other, the movement apart helping maintain the leak integrity of the diaphragm and the body.

BACKGROUND OF THE INVENTION 
This invention relates to fuel pumps and, more particularly, to a 
crashworthy fuel pump capable of withstanding extreme forces such as occur 
during a crash without leaking fuel. 
Because of their location in the engine compartment of an automobile, fuel 
pumps are susceptible to damage during a crash as the result of being 
struck by debris flying about in the compartment. As a consequence, fuel 
leaks from the pump may occur. The presence of gasoline in the engine 
compartment due to a broken fuel pump creates a great risk of fire and 
potential harm to both the vehicle and its occupants. 
Federal Motor Vehicle Safety Standard (FMVSS) 30 was issued in an attempt 
to reduce the hazards attendant the location of the fuel pump in the 
engine compartment by requiring that the risk of damage to a fuel pump 
during a crash be minimized. To comply with this standard, various schemes 
have been proposed to shield the fuel pump or otherwise protect it from 
flying debris. However, these protective shields add weight to the 
vehicle, may be difficult to fit into already crowded engine compartments, 
and may not always prevent an object from striking a fuel pump. 
SUMMARY OF THE INVENTION 
Among the several objects of the present invention may be noted the 
provision of a fuel pump which is crashworthy; the provision of such a 
fuel pump to not leak fuel when struck by an object during a crash even 
though the fuel pump is deformed; the provision of such a fuel pump which 
has substantially the same envelope as a conventional, non-crashworthy 
fuel pump so as to be readily installed in the engine compartment of a 
vehicle and take up substantially the same space therein; and the 
provision of such of a crashworthy fuel pump which reduces or eliminates 
the need for protective shields or similar devices. 
Briefly, a crashworthy fuel pump of the present invention is for use in an 
automotive fuel system comprises: a body having a first portion in which 
is formed a fuel intake cavity and a fuel discharge cavity and a second 
portion in which is formed a fuel pumping chamber. One end of each cavity 
is in fluid communication with the pumping chamber and the second portion 
of the body has an open end around the periphery of which is formed a lip. 
A flexible diaphragm closes the pumping chamber, the diaphragm being 
insertable into the open end of the second portion of the body and the lip 
being bendable over the outer margin of the diaphragm to clamp the 
diaphragm within the body. Means are provided for flexing the diaphragm to 
pump fuel into and out of the pumping chamber through the respective 
intake and discharge cavities. The flexing means are housed in a housing 
having one end formed for abutment with the open end portion of the body. 
The body and the housing are clamped together to form a unified assembly. 
The clamp is sufficiently strong to hold the assembly together when the 
assembly is subjected to normal forces, the breaks apart when the assembly 
is subjected to abnormal forces such as occur during a crash whereby the 
housing and the body can move apart from each other, the movement apart 
helping maintain the leak integrity of the diaphragm and the body. Other 
objects and features will be in part apparent and in part pointed out 
hereinafter.

DESCRIPTION OF A PREFERRED EMBODIMENT 
Referring to the drawings, a fuel pump F for use in an automotive fuel 
system comprises a pump body, generally indicated B, which is of 
one-piece, thin-walled, sheet metal construction. Body B has a first 
portion P1 in which are formed two integral deep-drawn cylindrical, 
cup-shaped projections, one of which is partially shown in FIG. 1 and is 
indicated by reference numeral 1. Referring to FIG. 3, projection 1 
defines an intake cavity for the fuel pump and a second projection 2 
defines a discharge cavity for the pump. A properly oriented check valve 
(not shown in FIG. 1) is located in each cavity to control fuel flow into 
and out of the fuel pump and appropriate fittings (also not shown) are 
located at the outer end of each projection for connecting the fuel pump 
into the fuel system. Check valves and fittings of the type shown in U.S. 
Pat. No. 3,096,722 to Fitzgerald et al, issued July 9, 1963, are 
illustrative of those which may be used in fuel pump F. 
Body B has a second portion P2 of a shallow cup shape, having an end wall 3 
and a flaring annular peripheral wall 5 forming a fuel pumping chamber 7. 
One end of each cavity is in fluid communication with the pumping chamber. 
The lower end of body portion P2 is open and a lip 9 is formed around the 
periphery of this open end. 
An annular diaphragm 11 closes pumping chamber 7. The diaphragm consists of 
a relatively thin disk of flexible, fuel-resistant material such as a 
suitable synthetic rubber. In its unstressed condition the diaphragm is 
essentially flat. The diaphragm is insertable into the open end of the 
second portion of body B. As shown in FIG. 1, lip 9 of the pump body is 
bendable over the outer margin of the diaphragm to clamp the diaphragm 
within the pump body. The entire outer margin of the diaphragm is so 
clamped and the result is a fluid-tight seal between the pump body and the 
diaphragm. 
Means, indicated generally 13, flex diaphragm 11 to pump fuel into and out 
of the pumping chamber 7 through the respective intake and discharge 
cavities. Means 13 comprises a diaphragm actuating rod 15 and a spring 17. 
Diaphragm 11 is sandwiched between a pair of backing plates 19 and 21 
respectively. Rod 15 extends through the backing plates and the diaphragm 
and the end of the rod is spun over as indicated at 22. One end of spring 
17 seats against the underside of plate 21. A rocker arm 23 is operable by 
an engine driven eccentric cam (not shown). The inner end of the rocker 
arm is attached to the other end of rod 15 and pulls the rod downward as 
it is rocked by the cam. This pulls diaphragm 11 downwardly and creates 
the intake stroke of the pump. Spring 17 pushes the diaphragm upwardly at 
the end of the intake stroke to produce the discharge stroke of the pump. 
Means 13 is housed in a housing 25. the housing has a hollow conical pump 
head 26. The pump head has an outwardly extending circumferential rim 27, 
the upper face of which is downwardly and outwardly sloped. At the base of 
the slope is a shallow groove 29. The groove and slope form a seat for the 
diaphragm/pump body assembly and, in particular, the slope and groove are 
shaped to accommodate the bent-over portion of lip 9 after diaphragm 11 is 
clamped to the pump body. 
A means, indicated generally 31, clamps body B and housing 25 together to 
form a unified fuel pump assembly. As shown in FIG. 2, clamping means 31 
comprises a circular ring 33 which is fitted around the body and the 
housing to join the two together. Ring 33 has an inturned, lower margin 
forming a lip 35. The inner face of this lip abuts the bottom outer 
surface of lip 27 when the pump is assembled. The ring has an upwardly 
extending circumferential side 37 whose height is such that the side 
extends beyond the joining surfaces of body B and housing 25. The upper 
portion of side 37 is crimped over the top of body B after the body and 
housing are brought into abutment so as to clamp the body and housing 
together as shown in FIG. 1. 
Ring 33 has sufficient strength so as to keep the fuel pump assembly 
together when it is subjected to the normal forces encountered during 
ordinary operations of the vehicle in which the fuel pump is installed. 
Ring 33 have at least one point of structural weakness such as the line of 
weakness indicated at 39 in FIG. 2. This causes the ring to break apart 
when the pump assembly is subjected to abnormal forces such as those which 
occur during a crash. When the ring breaks, body B of the fuel pump may 
move away from the housing portion of the pump and this movement apart 
helps maintain the leak integrity between diaphragm 11 and the body. Were 
the body and housing held together in the conventional manner, no 
separation will occur between the body and housing and the body may be 
deformed or ruptured by flying debris inside the compartment where the 
pump is installed with a fuel leak resulting. By employing a clamping 
means such as ring 33, the body portion of the fuel pump is able to move 
with the result that it will be less severely damaged if struck by debris. 
Further, the seal formed between the diaphragm and body prevents fuel 
leakage when the body is separated from the housing. In addition, backing 
plate 21 has a circumferential skirt 39, the height of which is 
sufficiently great so the outer end of the skirt cannot contact the 
diaphragm even if the body of the fuel pump is deformed. This prevents the 
diaphragm from being punctured by the skirt and thus further safeguards 
against fuel leaks. 
Finally, the check valves located in the inlet and discharge cavities may 
be replaced with control valves 41 (see FIG. 3) such as those disclosed in 
patent application Ser. No. 885,886, filed Mar. 13, 1978, and assigned to 
the same assignee as the present application. Control valves of the type 
disclosed in this application replace the conventional check valves 
located in the intake cavity of the fuel pump, the discharge cavity, or 
both. In any event, control valves 41 are designed to withstand large 
heads of fuel without permitting leaks and thus prevent fuel from entering 
cavity 7. This further reduces the possibility of a fuel leak occurring 
during or after a crash. 
A fuel pump of the invention occupies the same space in the engine 
compartment as a conventional non-crashworthy fuel pump and, in addition, 
eliminates or reduces the need for protective shields or barriers whose 
purpose is to prevent flying debris from striking the fuel pump. 
In view of the above, it will be seen that the several objects of the 
invention are achieved and other advantageous results obtained. 
As various changes could be made in the above constructions without 
departing from the scope of the invention, it is intended that all matter 
contained in the above description and shown in the accompanying drawing 
shall be interpreted as illustrative and not in a limiting sense.