Drive pulley for improved service of engine mounted accessories

Coolant pump service in a crowded engine compartment is provided by forming the side wall of the pump drive pulley with a centralized and radially lobed opening which can accommodate the radial arms of the drive hub that are normally connected by screws to the pulley side wall. The drive hub is fixed to the outboard end of the coolant pump drive shaft that extends through the housing of the pump that is removably secured by screws to the block of an internal combustion engine. The pump impeller is mounted on the inboard end of the drive shaft for fluid pumping operation in a coolant-receiving cavity in the coolant circuit of the engine. In the event of interference, which prevents or hampers the removal of the pulley axially from the drive shaft, the hub screws are removed and the pulley is turned into alignment with the lobes of the opening so that the pump housing screws are accessible. These screws are then removed so that the pump can be manually removed from the clearance between the engine and the frame side rail or other interfering component.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to drive pulleys for augmenting service of 
associated belt-driven accessories mounted on the engine in crowded 
vehicle engine compartments and more particularly to a new and improved 
drive pulley and pulley hub for the liquid coolant pump operatively 
mounted on the engine block that allows the pulley to be disconnected from 
the drive hub and displaced inboard to a position on the pump housing to 
provide ready access to pump attachment screws for augmenting their 
removal and removal of the pump from the block of the engine. 
2. Description of Related Art 
Prior to the present invention, various coolant pump designs for internal 
combustion engines have been devised to provide effective engine cooling 
during a wide range of engine operations. U.S. Pat. No. 5,537,956 issued 
Jul. 23, 1996 for "Coolant Circuit" and U.S. Pat. No. 5,409,350 issued 
Apr. 25, 1995 for "Water Pump Bearing and Seal Cartridge" as well as the 
"Cooling System" shown in the Figure on page 346 of Auto Service and 
Repair, c. 1984, by the Goodheart--Wilcox Co. Inc., exemplify such 
designs. While these prior designs generally meet their design objectives, 
they do not address new and higher standards for improved coolant pump 
service in crowded spaces particularly in an engine transversely mounted 
in an accessory packed engine compartment found in many modern automobiles 
with front wheel drives. 
BRIEF SUMMARY OF THE INVENTION 
The belt driven pulley of an accessory operatively mounted on the engine as 
set forth in this invention is readily removed from driving connection 
with the pulley hub and connected drive shaft of the accessory even though 
it may be in close quarters in a crowded engine compartment of a vehicle. 
With the pulley free, the retention screws holding the accessory to the 
engine are accessible and removed so that the accessory can be removed. 
More particularly, in some installations, the tight clearance between the 
outboard end of the coolant pump housing and a side rail of the vehicle 
frame with a transversely mounted engine hinders or precludes the ready 
disconnect and removal of the coolant pump pulley and subsequent removal 
of the pump from the engine block for service or replacement. This is 
remedied in the present invention by providing the side wall of the pulley 
with a multi-lobed opening which provides a window allowing the through 
passage of the separate pulley hub with its radial arms after their 
disconnect from the side wall of the pulley. With this invention, the 
following method steps may be employed for pump service. The pulley may be 
released from its hub by suitable tooling and is subsequently turned until 
the arms of the hub are aligned with the opening in the pulley. The pulley 
is then axially moved over the pulley hub and onto the coolant pump 
housing to provide access to the retention screws securing the pump body 
to the engine. After removal of the pump body retention screws, the pump 
can be axially withdrawn from the engine block and moved with the pulley 
telescoped aboard into the clearance between the engine and side rail and 
subsequently from the clearance to a completely free position for pump 
service or for pump replacement. 
In this invention the new and improved pulley and its associated pulley hub 
can be readily employed with a wide range of coolant pump designs or with 
other accessories since little or no modifications of the pulley driven 
components are required. 
These and other features, objects and advantages of the present invention 
will become more apparent from the following drawings, descriptions and 
specifications.

DETAILED DESCRIPTION 
Turning now in detail to the drawing FIG. 1 illustrates in side view an 
automotive internal combustion engine 10 as operatively mounted in the 
engine compartment 12 of an automotive vehicle. The engine compartment 
hood is represented by the dashed line 13. The engine 10 powers an 
accessory system drive pulley 14 driven through the engine crankshaft 
which in turn drives an coolant pump drive pulley 16, an air conditioner 
compressor drive pulley 18, a generator drive pulley 20 and a power 
steering gear pump drive pulley 22. The rotational drive for these pulleys 
is through a drive belt 24 routed in a serpentined and endless path around 
pulleys 16, 18, 20, and 22 and around belt tensioning pulley 26 and idler 
wheel 28. 
The side rail 32 of the frame of the vehicle is outboard of and so close to 
the coolant pump drive pulley 16 that only tight clearance is available 
for service of the engine-mounted coolant pump 34 and its drive pulley 16. 
FIG. 2a illustrates service problems related to such tight clearances in 
which the clearance 36 between the block 37 of engine 10 and the adjacent 
side rail 32 is not adequate to allow the ready removal of a prior drive 
pulley 40 from the prior pump drive hub 42 and the subsequent removal of 
the pump 34 from the engine block for pump replacement or service. 
With such prior construction there is initial difficulty in accessing and 
removing the screws 43 attaching the pulley 40 to the pulley hub 42. 
Moreover, since the prior pulley 40 covers the pump 34, the screws 44 
attaching the pump 34 to the engine block are not readily accessible for 
their removal so that the pump cannot be easily removed from the engine 
block. 
In this invention, however, removal of the pump pulley from the pulley hub, 
and more importantly, the subsequent removal of the pump from the engine 
is augmented by the improved method of pump service and by the design of 
the pump pulley 16 and the associated pulley hub 46 best illustrated in 
FIGS. 1-5. In the preferred embodiment of this invention, the outer side 
48 of the pulley 16 is formed with a generally circular opening 50 
enlarged by three radial and arcuately spaced lobed openings 52. This 
enlarged opening is designed to match, with clearance, the pulley hub 46 
with its three radial and arcuately spaced arms 56 each drivingly 
connected to the coolant pump pulley 10 by screws 58. As shown best in 
FIGS. 2, 4 and 5, the end portions of each of the radial arms is stepped 
in an inboard direction to provide offset seat 60 for improved seating and 
attachment of the pulley to the hub. This offset seat construction and the 
inwardly offset side 48 of the pulley effectively moves the pulley-hub 
attachment in an inboard direction closest to the engine 10 providing 
increased clearance for tooling to access screws 58. 
The pulley hub 46 is drivingly secured to the outboard end of the pump 
drive shaft 62 that is rotatably mounted by bearing 64 in an axial bore 66 
formed in the generally conical and laterally extending hub portion 68 of 
the body of the pump or housing 70. A fluid seal 71 operatively mounted in 
the inboard end of the bore fluid seals to the drive shaft and prevents 
fluid leakage from the pump 34. The conical hub portion 68 extends from a 
flattened base portion 72 of the housing into the confines of the pulley 
16 as defined by the multi-grooved cylindrical rim 74 of the pulley and 
its side 48 as best shown in FIGS. 2 and 4. 
As shown best in FIG. 2b, the base portion 72 of the housing has radially 
extending and arcuately spaced attachment ears 80, 81 formed with openings 
82 that receive screws 44 that secures the pump housing 70 to the block of 
the engine. 
The pump 34 further comprises a multi-bladed impeller 86 secured to the 
inner end of the drive shaft 62 which is disposed in a pumping cavity 88 
formed in the block of the engine that is part of the engine coolant 
circuit. With this construction, the rotation of the pulley 16 by the 
drive belt will effect rotation of the impeller to circulate coolant in 
the circuit for engine and component cooling purposes as well as for the 
selective heating of the occupant compartment of the vehicle. 
For service of the coolant pump 34 the screws 58 securing the pulley 16 to 
the pulley hub 46 are accessed. This can be readily accomplished by 
removing the drive belt 24 from the rim or periphery of the pulley and 
turning the pulley until each of the pulley hub screws 58 is moved to 
their most accessible position with respect to the side rail 32. This 
position is shown in FIG. 2 in which upper screw 58 is accessible. This 
screw is removed and the pulley is turned in index fashion so that the 
other two screws are accessed and in turn removed. After of the screws 58 
are removed, the pulley 16 is turned to effect alignment of the lobes of 
the opening 52 with the radial arms 56 of the hub 46. On such alignment, 
the pulley 16 is axially displaced in an inboard direction so that the 
pulley hub 45 passes through the window provided by the opening 50 in the 
pulley and onto the conical hub portion 68 of the pump housing as shown 
best in FIGS. 4 and 5. Tools such as the ratchet 96 and socket 98 can then 
be inserted through the lobed opening in the side 48 of pulley 16 to 
remove the screws 84 holding the pump housing to the engine block. After 
removal of the screws 44, the pump 34 with the pulley 16 telescoped aboard 
are axially withdrawn and moved into the clearance 36 between the side 
rail 32 and the engine block, shown in FIG. 6. The components can be 
subsequently moved into a free work area for pump repair. The serviced or 
replacement pump can be easily reinstalled by reversing the service steps 
outline above. 
While a preferred embodiment of the invention has been shown and described, 
other embodiments will now become apparent to those skilled in the art. 
Accordingly, this invention is not to be limited to that which is shown 
and described but by the following claims.