APPARATUS FOR LEAKAGE TESTING THE COOLING CIRCUIT OF CYLINDER HEADS OF INTERNAL COMBUSTION ENGINES

Abstract: The apparatus comprises a pivotable bench (2) about a horizontal axis, which includes longitudinal stringers (5) hold­ ing a cylinder head (6) to be tested. Mounted for oscillation on the pivoting bench (2) there are means for fastening to the cylinder head a top plate (9) to seal off the cylinder head cooling ports. The plate (9) has fittings (22a, 22b) for admitting a pressurized test fluid through the cylinder head cooling circuit. The pivoting bench (2) further includes air cylinders (25) for fastening small side cover plates (27, 28) to the cylin­ der head for sealing the cooling circuit side ports.

Description: "APPARATUS FOR LEAKAGE TESTING THE COOLING CIRCUIT OF CYLINDER HEADS OF INTERNAL CON3USIION ENGINES" This invention relates to an apparatus for leak or leakage testing the cooling circuit of cylinder heads of internal combustion engines. It is a known fact that engine cylinder heads may develop cracks which impair their cooling circuit tightness. It is current practice to test leaks by manually closing all of the ports in the cylinder head and introducing through the head cooling circuit water heated to a temperature in the 400C to 800C range, which is then pressurised by means of compressed air. A leak in the head would be notified by a pressure drop measured with suitable meters, as well as detected visually and acoustically by fluid seepage around a crack. This test is apparently a time-consuming and labour-consuming one owing to the need for sealing off one by one the many ports in the cylinder head and for shifting manually the cylinder head to inspect any leaky spots. Thus, the task of this invention is to obviate that problem by providing an apparatus which affords the possibility of leakage testing the cooling circuit of cylinder heads of internal combustion engines ina uick and easy manner. Within that task it is anobÅaect of the inventionto provîde such an apparatus which is simple in design, convenient and reliable to use, and versatile in application to different engine types. These task and object are achieved, according to the invention, by an apparatus for leak testing cylinder heads of internal combustion engines, characterised in that it comprises a pivoting bench about a horizontal axis including means for holding a cylinder head to be tested, means mounted for oscillation on said pivoting bench and adapted to fasten to said cylinder head a cover plate sealing off top ports of the cylinder head cooling circuit, said plate being provided with fittings for admitting a pressurised test fluid through said cooling circuit, and means for fastening to said cylinder head small cover side plates sealing the side ports in said cooling circuit. Further features of the invention will be apparent from the following detailed description of a preferred embodiment of this leak test apparatus, as illustrated in the accompanying exemplary drawings, where: Figure 1 is a front view of this apparatus; Figure 2 is a side view of this apparatus; Figure 3 is a sectional view taken along the line III-III of Figure 2; and Figure 4 is a plan view of the cover plate from the side thereof mating with the cylinder head. With reference to the drawing figures, this apparatus for leak testing cylinder heads of internal combustion engines includes a base 1 having suitable drive members mounted therein, as explained hereinafter. Mounted on the base 1 is a pivoting bench, generally indicated at 2, which comprises a pair of coaxial rims 3a,3b to the interiors whereof a respective quadrilateral frame 4 is secured. Carried between two corresponding sides of the frames 4, and rigidly attached thereto, are two parallel stringers 5 for supporting a cylinder head to be tested and indicated at 6. The stringers extends outwards beyond the rim 3a, and one of the stringers 5 has an adÅaustable detent 7 mounted thereon. The rims 3a,3b bear on respective roller pairs 8 which project frontally, on opposed sides, from the base 1. The rollers 8 are keyed (Figure 3) to two parallel shafts 9 which are journalled in the base 1 on a common horizontal plane. The shafts 9 are adapted to be driven simultaneously by the motor 10 through a chain drive 11aS11b. Carried rotatably between the frames 4 of the pivoting bench 2 are, on the remote side from the stringers 5, two shafts 12. The shafts 12 have attached to their ends, outside of the rims 3a,3b, respective cross arms 13a,13b. Pivotally connected to the free ends of the arms 13a and 13b are the bottom cap and piston rod, respectively, of a respective air cylinder 14a,14b operative to produce their oscillation. The arms 13b are also connected to a linkage 15 which is pivoted to its respective frame 4 and effective to ensure that the arm angular displacements occur symmetrically. A plurality of bushings 16 are mounted on the shafts 12 which are slidable along, but not rotatable around, the shafts. Projecting from each bushing 16 is a cross arm 17 having a pusher foot 18 articulated thereto. The feet 18 are adapted to act on a cover plate 19 for covering the upper ports in the head 6. As shown in detail in Figure 4, the cover plate 19 is formed on one face thereof, intended to contact the head 6, with 2 plurality of seats 20 for sealing gaskets corresponding to the ports of the cylinder head cooling circuit. to threaded holes 21 are in communication with said cooling circuit, which are surronnded by respective sealing gaskets and adapted to receive quick-connection fittings 22a,22b threadably therein. ,41so provided, for accurately locating the plate on the head, are two throughgoing holes 23 for respective locating pins. The plate 19 is also formed with lightening cutouts 24. For closing the cylinder head side ports7 air cylinders 25 are provided on one side which are mounted, at an adjustable position, transversely to an additional longitudinal stringer 26 secured between the frames 4. The piston rods of the cylinders 25 are adapted to operate small plates or plugs 27 for application against the cylinder head. On the opposite side, a further pair of plates 28 are provided which are adapted to bear against respective detents 29 carried respectively on small shafts 30 which are mounted slidably on the frame 4, lengthwise to the pivoting bench 2. The apparatus further includes a test hydraulic fluid recirculating pump 31, accommodated in the base 1. A swinging arm 32 carrying a test control panel 33 is also articulated to the base 1. The apparatus described hereinabove operates as follows. The plate 19 covering the upper ports and side port cover plates 27 and 28 are attached to the cylinder head, being located thereon by means of suitable locating pins. Of course, said cover plates, a large one and small ones, are specifically constructed for different types of internal combustion engines. The cylinder head 6 is then placed on the supporting stringers 5 of the pivoting bench 2 and pushed against the detent 7 in contact therewith. Then, by sliding the respective supporting members, one positions the pressure feet 18 on the plate 19 and the pistons 25 and detents 29 at the respective plates 27 and 28. At this point, the cylinder head clamping is ordered by actuating the air cylinders 25 and then those 14a,14b which effect rotation of the shafts 12. Thus, the cylinder head cooling circuit ports are sealed by the plate 19 and small plates 27 and 28 provided with suitable sealing gaskets; should the small plates 27 and 28 fail to cover all of the side ports, the closure should be effected by means of conventional manually threaded shutters. After clamping the head firmly, the compressed air system is connected, by means of a suitable cable equipped with quick-connect fittings, to the fitting 22a on the plate 19. ty supplying the pressurised air into the cooling circuit, one can ascertain, both acoustically and by the pressure drop monitored by a pressure gauge on the control panel, the presence of possible cracks. To locate the faults detected, after discharging the compressed air, one connects to the fitting 22b the test hydraulic fluid, usually water, delivery system, and a conventional overflow pipe to the fitting 22a so as to ascertain the filling of the cylinder head with fluid. After removing the overflow pipe and again connecting the compressed air to the fitting 22a, the water in the cooling circuit is pressurised, To facIlitate locating cracked spots whence water flows out, the bench 2 on which the cylinder head is clamped is turned. The discharge water is collected in an upper tank 34 of the base 1. Thus, this apparatus enables the leak test to be carried out in a rapid manner, because the cooling circuit is closed automatically, and without effort even with large size and heavy cylinder heads, thanks to the pivoting bench on which the head is mounted. Clamping of the cylinder head on the pivoting bench provides, moreover, safety for the operator. The cylinder head may also be hot tested: the test may be, in fact, carried out after, by means of the pump 31, heated water has been circulated, which would be heated in an insulated tank 35 served by the same pump and an el ectric resistance heater, at desired temperature. It should also be noted that it is possible to effect on the cylinder head, as mounted on the bench, the preliminary operations to grinding which are normally carried out in a difficult manner. In practicing the invention, the materials, shape and dimensions may be any ones depending on requirements.

Claims: CLAIMS 1. An apparatus for leakage testing the cooling circuit of cylinder heads of internal combustion engines, characterized in that it comprises a pivoting bench (2) about a horizontal axis including means (5) for holding a cylinder head (6) to be tested, means mounted for oscillation on said pivoting bench (2) and adapted to fasten to said cylinder head (6) a cover plate (19) sealing off top ports of the cylinder head cooling circuit, said plate (19) being provided with fittings (22a,22b) for admitting a pressurized test fluid through said cooling circuit, and means for fastening to said cylinder head (6) small cover side plates (27,28) sealing the side ports in said cooling circuit. 2. An apparatus according to Claim 1, characterized in that said pivoting bench (2) comprises a pair of coaxial rims (3a,3b) carnring internally respective frames (4) wherebetween parallel stringers (5) are attached at the bottom for supporting said cylinder head (6) and a pair of shafts (12) are carried rotatably at the top having oscillating means (16) for claping said cover plate mounted thereon, said shafts (12) being adapted for simultaneous oscillation in opposite directions on actuation of air cylinders (14a,14b) articulated to arms (13a,13b) attached transversely to the ends of said shafts (12). 3. An apparatus according to the preceding claims, characterized in that said oscillating clatnping means for said cover plate (19) comprises a plurality of bushings (16) mounted slidably on said shafts (12) and having respectively a cross arm (17) carrying a pressure foot (18) articulated thereto. 4. An apparatus according to Claim 1, characterized in that said clamping means (16) for said side plates (27,28) comprise on one side a pair of detents (29) which are adjustable longitudinally to said pivoting bench (2), and on the opposite side a plurality of air cylinders (25) mounted, at adjustable positions longitudinally to said pivoting bench (2), transversely to the axis of said pivoting bench (2). 5. An apparatus according to Claim 1, characterized in that said cover plate (19) has1 on one face mating with said cylinder head, a plurality of seats (20) for sealing gaskets corresponding to said ports of the cylinder head cooling circuit and has thwoughgolag holes (21) for said test fluid delivery fittings (22a,22b) and cylinder head locating pins formed therein. 6. fin apparatus according to at least Claims 1 and 2, characterized in that said rims (3a,3b) of said pivoting bench (2) are mounted on respective pairs of rollers (8) carried rotatably on a base of the attpatatus and being adapted for simultaneous drive off a motor means. 7. An apparatus for leakage testing the cooling circuit of cylinder heads of internal combustion engines according to the preceding claims and substantially as herein described and illustrated.

Inventors: SBARZAGLIA, GIOVANNI
Applicants: SBARZAGLIA, GIOVANNI
Application year: 1984
Main classification: G01M3
IPC codes: G01M3