US3447408A - Method and apparatus for piercing blanking fuel pump diaphragms - Google Patents

Description

June 3, 1969 w PARRENT ETAL 3,447,408

METHOD AND APPARATUS FOR PIERCING BLANKING FUEL PUMP DIAPHRAGMS Filed March 21, 1966 95 7187 j 30 i 47 I INVENTORSE ROBERT J. GRAY WILLIAM RUSSELL PARRENT ATTORNEY United States Patent 3,447,408 METHOD AND APPARATUS FOR PIERCING BLANKING FUEL PUMP DIAPHRAGMS William Russell Parrent and Robert J. Gray, Fair-field,

111., assignors to Airtex Products, division of United Industrial Syndicate, Inc., a corporation of New York Filed Mar. 21, 1966, Ser. No. 541,903

Int. Cl. B26d 7/14, /08

U.S. CI. 83-21 7 Claims ABSTRACT OF THE DISCLOSURE A problem exists in the assembly of fuel pumps having so-called loop diaphragms in that, due to the loop in the rubberized sheet material generally referred to as diaphragm cloth, the loop formation which may be effected in various ways causes an unevenness in the circular margin of the diaphragm surrounding the loop in the circural margin of the diaphragm surrounding the loop or arch. This unevenness is due to the fact that the arch is drawn into the fuel chamber and the marginal surrounding area is clamped between flanges of the body castings of the fuel pump. The transition of shape from arched condition causes wrinkles and leakage.

The present invention overcomes this drawback of the prior art by blanking and punching the diaphragm between forming dies in such a manner that diaphragm cloth is fed from a long strip or web to a pair of mating dies which form the loop positively and uniformly in each diaphragm area to hold the diaphragm area in position corresponding to the position it will occupy in an assembled pump. While so held, the diaphragm is blanked and pierced and the holes thus punched correspond to the hole position of the castings which take the threaded bolts during assembly. Accordingly, by such piercing the holes are arranged in a perfect circle to mate with the casting holes while at the same time the diaphragm cloth is positioned by the forming dies and the margin surrounding the loop is held flat during piercing so as to eliminate or minimize any wrinkling effect when the diaphragm is assembled between the pump castings.

Other objects and features of the invention will be apparent from the description that follows in which:

FIG. 1 is a vertical section in elevation of a compound blanking and piercing die having loop forming dies and having blanking and punching dies, for effecting the method of the invention;

FIG. 2 is a plan view of the upper head of the compound die;

FIG. 3 is an inverted plan view of the upper head of the compound die; and

FIG. 4 is a plan view showing a diaphragm blanked and punched as effected by the apparatus of the invention and in accordance with the method thereof, and being shown concentric in coaxial relation with a true circle.

Referring to FIGS. 1-3, the bed of a stamping press is indicated by the reference character and it supports a lower forming die which coacts with an upper forming die 20. It will be noted that a loop or bight 23 of an area of diaphragm cloth 26 is formed between the com- 3,447,408 Patented June 3, 1969 "ice plementary formations of the forming dies 15 and 20. Thus, the die 15 has a flat annular shoulder 15a coacting with a protruding ridge 20a of die 20 to form the loop 23. It will be understood that diaphragm cloth in the form of a strip or web is fed from left to right between the dies, the die 20 being raised a suflicient distance by means of the press head 30 so as to effect a feed gap between the upper and lower forming dies.

The upper forming die 20 has a shoulder in the form of an annular flange 33 which coacts with an inner annular flange 36 formed concentrically within a coacting cutting or blanking die 40. The aforementioned shoulders are normally biased against each other by means of springs 44 socketed in the press head 30 and bearing outwardly against the upper surface of the die 20. The coacting cutting die 40 is bolted as by bolts 47 to the head 30. Accordingly, when the head is raised the shoulder 33 is forced against the shoulder 36 by springs 44, which latter shoulder then raises the die 20 in the course of upward movement of head 30. However, on downward movement of the head, assuming that an area of diaphragm cloth has been fed below die 20, not only will the loop 23 be formed but the marginal area of the material around the loop will be held flat and gripped between the shoulder 50 of die 20 and the upper annular surface 53 of a die member 55 bolted by bolts 57 to the press bed 10. In that manner the area of the cloth which is to be punched and blanked is securely held in a loop. Subsequent to the forming of the loop the cutting die 40 having the female cutting edge 60 blanks the diaphragm, the outer edge of die 55 being the male cutting edge. At about the same time a series of punches 65, arranged in a ring, punch holes in the clamped margin of the diaphragm area. The holes are for bolt passage when the diaphragm is assembled between the body castings of a fuel pump in the usual manner. The die member 55 has tapering bores 67 to effect a female die for punches 65, and to permit egress of punchings. Likewise, a centrally disposed punch 68 punches a hole in coaction with the female die bushing 71, such hole being for the actuating stem of the diaphragm to be secured in the central area. The female die member 71 is carried as by force fit in the lower forming die 15.

From the above description, it will be apparent that the lost motion provided by the gap between shoulders 33 and 36 effect initially a forming of the diaphragm loop 23 by dies 15 and 20 followed by blanking of the diaphragm disc and punching of the holes.

The punches are carried in a plate 75 fastened as by bolts 78 to the head 30.

A stripper plate 80 is carried on slidable pins 83 disposed in suitable bores in the bed 10 and a series of compression springs 86 bias plate 80 upwardly so that its upper surface is initially level with the surface of the die 55. Thus, the heads of the bolts 83 move downwardly a distance corresponding to the gap 87 when the blanking die 40 pushes downwardly in the course of cutting at the edge 60.

The lower forming die 15 may be carried as by force fit within the die 55 or it may be bolted to the bed 10.

Various locating pins, such as pins 93 and 95, are utilized in a conventional manner for the purpose of accurately locatingthe several components to be boltedly assembled. A stop pin is carried in bed 10 to serve as a measuring device for each increment of cloth disposed in the die.

Referring to FIG. 4, the effect of forming the loop in the diaphragm between the forming dies followed by subsequent blanking and punching is shown. It will be noted that a non-circular shape results as compared with the phantom line true circle. Thus, there is a deformation of the diaphragm area which results in slight flattening from a truly circular are at four edge portions or areas. This does not effect the operability of the diaphragm when assembled in a pump but enhances the forming of the loop in the course of assembly with the pump castings. Thus, the diaphragm may be put between the body castings with the holes in register therewith and the diaphragm stem pushed down after which the bolts are inserted and tightened with the diaphragm stem in downward position, that is, in the position it would have at the end of a discharge stroke.

The particular mode of assembly just described is not the only one which could be used, but is merely set forth for illustrative purposes.

FIG. 4 shows four flattened areas for a diaphragm, this being the condition which obtains for one type of commercial fuel pump; other pump types which may use diaphragms of dilferent diameter, thickness and more or less holes might have more or less than four edge portions of decreased arcuateness. The phantom line circle in FIG. 4 can be considered as representing the cutting edge of the blanking die, the material of the diaphragm being circumscribed thereby.

We claim:

1. A method of piercing and blanking loop type diaphragms which comprises clamping an area of diaphragm cloth in sheet form out of its normal plane into a loop configuration corresponding generally to the configuration of the diaphragm when assembled in a fuel pump, and blanking the area with a circular die and punching the margin of the area to provide bolt holes therethrough adjacent the periphery thereof, wherein the resulting separated diaphragm is essentially non-circular in perimeter and wherein the holes therethrough are essentially located in a circle.

2. A method as set forth in claim 1, including punching a hole centrally of the clamped area for accommodating a fuel pump stem.

3. A method of preparing diaphragms from sheet material and having a bight formation when assembled in a fuel pump which comprises effecting a bight formation in a piece of diaphragm cloth out of its normal plane, holding a marginal area surrounding said formation in clamped condition, punching a series of holes around said formation in said marginal area in position to register with bolt holes of a fuel pump casting in which said diaphragm is to be assembled.

4. A method as set forth in claim 3, including the step of blanking said diaphragm to separate it from material surrounding said holes.

5. An apparatus for blanking and piercing fuel pump diaphragms of the type having a loop formation which comprises upper and lower loop forming dies between which an area of diaphragm cloth is clamped to effect an annular loop configuration out of the plane of said cloth, a blanking die surrounding one of said latter dies and a plurality of punches disposed interiorly of said blanking die.

6. An apparatus as set forth in claim 5, wherein said blanking die and one of said forming dies have abuttable shoulders, a moveable die head, said blanking die being integrally secured thereto, spring means intermediate said upper forming die and said die head for normally effecting abutment of said shoulders, whereby when said upper forming die clamps diaphragm cloth between itself and said lower die said shoulders move relative to each other by compressing said spring means and said blanking die severs the diaphragm area from said cloth.

7. In an apparatus as set forth in claim 6, said plurality of punches being carried by said movable die head, said upper forming die having bores through which said punches are slidable to engage the diaphragm area for punching holes in the diaphragm cloth.

References Cited UNITED STATES PATENTS 124,669 3/ 1872 Delkescamp 8321 1,746,043 2/1930 Maguire 83-637 X 2,100,683 11/1937 Bierwirth 83-621 X 3,234,774 2/ 1966 Margedant.

ANDREW R. JUHASZ, Primary Examiner.

US. Cl. X.R. 83-176, 6 21

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