US2740388A - Temperature control mechanism for liquid cooled engines - Google Patents

Description

April 3, 1956 G. D. BENNORTH 2,740,388

TEMPERATURE CONTROL MECHANISM FOR LIQUID COOLED ENGINES Filed Sept. 8. 1951 2 Sheets-Sheet 1 IN V EN TOR.

HIS ATTORNEY April 3, 1956 G. D. BENNO'RTH 2,740,388

TEMPERATURE CONTROL MECHANISM FOR LIQUID COOLED ENGINES Filed Sept. 8. 1951 2 Sheets-Sheet 2 a predetermined minimum temperature. object of the present invention to provide temperature TEMPERATURE CONTROL MECHANISM FOR LIQUID COOLED ENGINES George Df'Bennorth, Los Altos, Caiif. Application September 8, ESL-Serial No. 245,708

7 Claims. (Cl. 123-4112) The-present invention relates to temperature control mechanism,-and pertains more particularly to an arrangement for controlling'the temperature of the coolant of a liquid cooled, internal combustion engine.

It is a matter of common knowledge that the lubricating qualities of most lubricants when cold, are greatly reduced from those qualities when the lubricant is heated to a proper operating temperature. The lubricating qualities of'the types of lubricants ordinarily used in internalcom- -bustion engines vary with temperature changes to such an extent that tests have indicated that one mile of operation with an extremely cold engine will sometimes produce as much engine wear as 300 miles of driving with the lubricant at proper operating temperature.

Although the voperation of the engine generates a sub- --stantial amount of heat, this heat normally is transmitted to the liquid coolant in the water jackets surrounding the cylinders, which liquid-is then conveyed, by the operation of the water pump ofthe engine, to the automobile radiator, where the heat is transmitted to the air driven through the radiator by the operation of the engine fan.

' In order to avoid this lossof heat during the early stages of operation of a coldengine', the present invention contemplates imm'obilizingthe fan and the rotor of the coolant pump until the coolant at the pump has attained It is also an controlled clutchmeans'for connecting the fan' and pump rotor of'an"internal combustion engine to a constantly driven drive means when the engine coolant is above a "predetermined temperature, and to disconnect the fan and pump from the drive'means'when the coolant is below suchpredetermined temperature.

Y it is a further object of the invention to provide a hollow shaft, having a fan and a coolant pump rotor secured thereto, with athermostatically controlled tapered cam '"forcon'trolling the operation of clutch means for connect- 'ing'the' hollow shaft to, and disconnecting it from, a constantly driven drive member upon predetermined temperature variations in a cooling medium to which the thermostatic cam control is exposed.

These and other objects of the invention will be ap- -p'arent from the following description and accompanying drawings, wherein Fig. l is an elevational view showing the inner side of a 'fan blade assembly having a pair of clutch shoes and clutch actuating members mounted thereon, a central tubular support shaft and a thermostatically actuated cam 'member being shown sectionally, portions being broken away.

tatably mounted in a coolant pump housing, portions being broken away.

Fig." 3is a fragmentary view of a modified form of pumpimpeller and tubularsupport shaft having a modi- United States Patent O yond the cap 22,

fied form of a thermostatic control device assembleditherewith, the shaft and a hub portion of the impeller-being shown in section.

Fig. 4 is an exploded perspective viewof. the fanblade assembly shown iri'Figl 1, some of .the parts being-omitted and portions being broken away.

Fig' 5 is a front elevational view of the assembly shown in Fig. 2, portions being broken away.

Referring to the embodiment. of the invention shown in Figs. 1, 2, 4 and .5, a liquid coolant pump A is of a 'centrifugaltype commonlyemployed on internal com- For drawing the coolant liquid into the pump housing 10 from the motor block, not shown, and discharging it through the outlet 12, a usual rotary impeller 13 is mounted within the housing 10. on' a tubular shaft 15. The impeller 13 is secured to the shaft 15. by a set screw 18. A- yoke strap 19 on the impeller 13 extends transversely across the lower end of .the tubular shaft .15, the yoke being offset downwardly from the end of. the shaft 15 to admit coolant freely into the bore of thelshaft 15.

A friction reducing washer 21 is interposed between the hub of the impeller 13 and a removable closure .cap 22 which is fitted into an opening centrally of the. impeller housing 10 and is secured in position therein by cap screws 23.

The cap 22 is hollow, having a domed outer wall 25 and a flat inner wall 26. Openings 27 communicate between the interior of the hollow-cap 22 and the; interior of 'the pump housing 10. The cap 22 has a tubular central portion 28, the lower end 29 of the bore of which is of slightly reduced diameter to receive the tubular shaft 15 for rotation therein. The-mainupper portion 30' ofthei bore of this tubular central portion 28 of the cap 22is of a diameter closely to receive the lower portion of a tubular pulley support shaft 31 therein. A conventional sealing ring 32-is interposedbetween theinner end of the tubular pulley support shaft-31 and ashouldered offset Z9a'inthe bore of the central cap portion 28' between the reduced lower bore portion 29 and themain' upper bore portion'fil) thereof. Thedrive'pulley C is mounted to rotate freely on the portion of the tubular. shaft 31"which projects beand a friction reducing-washer 35"is1 interposed between the pulley C and the domed cap" 22.

The pulley C is driven constantly, during operation of the engine, not shown,'upon which the device'is intended to be mounted, by a usual V-belt '37. A central recess 38 in the pulley C is of substantially'uniformcross sectional shape as shown in Fig. 2. The peripheral"wall"39' surrounding this recess is cylindrical, and is co-axialwith the pulley C to form a clutch surface as will be described later herein.

A fan blade and clutch shoe assembly B. ismounted on the outer end of the shaft 15 to rotate therewith. "The assembly 3 comprises a fan blade mounting disk "40 having a thickened hub'portion 41. The-hub portion'fil of the disk 40 is fitted onto'the outer end-of the tubular shaft 15, and is secured to rotate therewith by a Woodruff key 42. A. friction reducingwasherii is interposed be tween the hub portion 41 of'the :disk il), and theouter end of the'pulley support tube 31, andthetcentral iportion of the 'pulley C. i A cap nut-minis:screwedontoztthe threaded outer end of. the. shaft 15and.is provided with a usual grease fitting 45 which is screwed into a threaded hole provided therefor centrally of the cap nut 44.

The peripheral margin of the disc 41) is inserted, with a free rotative fit, in an annular groove 47 in the drive pulley 33. The hub portion 41 of the disc 40 has a pair of diametrically opposite and aligned grooves 48 and 49 (Fig. 4) in the inner face thereof. vEach of these grooves is adapted slidably to receive one of a pair of clutch shoe actuating bars 50 and 51, respectively (Figs. 1, 2 and 4). The radially inner end portions of these clutch shoe actuating bars also are inserted, for free slidable movement, through openings 52 and 53 in opposite sides of the tubular shaft 15. The radially outer ends of the bars 50 and 51 bear against the inner sides of a pair of clutch shoes 54 and 55, respectively. Since the clutch shoes are similar to each other, one only thereof will be described in detail.

Each clutch shoe comprises a curved metal plate 57 having a clutch facing member 58 of friction material, mounted thereon. These clutch facing members may be of the type commonly employed for facing clutch and brake shoes. A mounting web 59 is provided on one end of each curved plate 57, the web 59 being pivotally mounted on a clutch shoe mounting pivot pin 64). The threaded end of the pivot pin 60 is screwed into a counter-bored threaded opening 61 in a mounting boss 62 formed on the inner side of the fan blade and clutch shoe mounting disc 40.

On the opposite end of each curved plate 57 from the mounting web 59 thereon, an eye 63 (Fig. l) is provided, and a coil spring 65 is connected in tension between the eye 63 and the mounting web 59 of the opposite clutch shoe. Stop pins 67, 67 are secured to project from the inner side of the disc 40 to limit the inward movement of the clutch shoes under the impulses of their springs 65, 65.

For forcing the clutch shoes outwardly into clutching engagement with the pulley C when the temperature of the liquid coolant attains a predetermined minimum temperature, a thermostatically controlled cam 70 is inserted for free slidable movement axially of the bore of the tubular shaft 15. Opposite sides of the outer end of the cam 70 are beveled as at 71 and 72 (Figs. 2 and 4) to engage correspondingly beveled radially inner ends 50:: and 51a of the clutch shoe actuating bars 50 and 51 (Figs. 1 and 4).

The axially inner end portion 73 of the cam member 70 is of reduced diameter, and is inserted with a close, gripping fit, into a helically coiled, thermostatic control element 75, which may be of the well-known bi-rnetallic type. The helical thermostatic element 75 has free operating clearance Within the bore of the tubular shaft 15,

liquid, also not shown, will fill the pump housing 10, and,

and the lowermost convolution 75a is hooked beneath the yoke 19 to anchor the eleemnt 75 and to draw the cam 70 axially into the bore of the shaft 15 when the thermostatic element contracts upon cooling.

A sealing gasket 77 and a supporting metal washer 77a therefor are inserted between the wedge-shaped cam 70 and the outer end of the thermostatic element 75 to prevent the escape of coolant liquid through the bore of the hollow shaft 15.

A plurality of fan blades 80 are secured to the disk 40 to extend radially therefrom. Each fan blade is secured to the disk 40 by a single rivet 81 (Figs. 2 and 5). Each blade has a pair of semi-spherical embossed por' tions 82, 82 on the inner end thereof and the disk 40 is provided with matching recesses 83 (Fig. 5) to receive these embossed portions 82, 82 to retain the fan blades against rotative displacement about their securing rivets 81.

The operation of the device is as follows:

Assuming that the coolant pump and fan assembly shown in Figs. 2 and 5 is mounted in a well-known manner on the cylinder block of a liquid cooled internal combustion engine of a well-known type, not shown; coolant by means of the openings 27, 27, also will fill the interior of the pump housing cap 22. Since the bore of the tubular shaft 15 is in open communication with the interior of the pump housing 10, the coolant liquid also' will fill the bore of the tubular shaft 15 out as far as the sealing washer 77, thereby tending to maintain the thermostatic element 75 substantially at the temperature of the coolant liquid. 1 i 1 The pulley C will be driven by the belt 37 to rotate continuously during operation of the engine upon which the device is mounted. i

When the engine is cold, the thermostatic element 75 will be caused thereby to contract axially, thereby drawing the wedge-shaped cam axially inwardly in the bore of the shaft 15 under the combined tension of the bi-rnetallic element 70 and the action of the clutch springs 65, 65. Axial retraction of the cam 70 permits the clutch actuating bars 50 and 51 to be moved radially inwardly in their respective notches 48 and 49 and through the openings 52 and 53 in the tubular shaft 15. This radially inward movement of the clutch actuating bars 50 and 51 allows the clutch actuating springs 65, 65 to withdraw the clutch shoes 54 and 55 clear of the clutch surface 39 surrounding the pulley recess 38.

The fan blade assembly B is free for relative rotation within the pulley C except when the clutch shoes 54 and 55 are in frictional engagement with the peripheral wall 39 surrounding the pulley recess 38. Therefore, upon starting the engine when the coolant is sufiiciently cold to cause the clutch shoes 54 and 55 to be withdrawn from contact with the clutch surface 39 of the pulley C, the fan assembly B including the clutch shoes 54 and 55, the shaft 15 and the pump impeller 13 keyed thereto will remain stationary.

It is common practice to provide relatively large clearance between the blades of pump impellers and the pump housing in pumps for circulating the coolant liquid of liquid cooled engines. This clearance usually is adequate to permit a convection flow of the coolant independently of circulation by the pump impeller. As the coolant liquid in the water jacket of the engine is heated by the operation of the engine, the impeller 13 being-inoperative due to the withdrawal of the clutch shoes 54 and 55 from the clutch surface 39, this heated coolant will flow upwardly into the pump housing 10, and thence into the cap 22 and the bore of the tubular shaft 15.

In this manner, the thermostatic element will be heated, causing it to expand axially. This axial expansion of the element 75 moves the wedge-shaped cam 70 outwardly, causing the diverging faces 71 and 72 of the cam 79 to push the clutch actuating bars 50 and 51 apart. This action forces the clutch shoes 54 and 55 radially outwardly into clutch engagement with the marginal wall 39 around the recess 38 of the rotatively driven pulley C, and causes the fan assembly B, the tubular shaft 15, and the pump impeller 13 to rotate with the pulley C. 'As these parts mounted on the shaft 15 rotate, centrifugal force urges the clutch shoes 54 and 55 outwardly into even tighter engagement with the wall 39 of the pulley recess 38 to establish a firm non-slipping driving relation therewith.

In the modified form of thermostatic control element shown in Fig. 3, a usual thermal expansion bellows is mounted within the central opening 91 of an impeller 92 which generally is similar to the impeller 13 shown in Fig. 2. A shaft 93 is secured to the impeller by a set screw 95, indicated in dotted lines in Fig. 3. The shaft 93 is mounted in a position where it will clear the bellows 90 even when the bellows is in its heated or expanded condition. The bellows 90 is of a well-known type adapted to expand when heated and to contract when cool. The upper end of the bellows 90 is connected to a rod 97, which is similar to the reduced inner portion 73 of the cam 70 described previously herein. The upper end of the rod 97, not shown, is adapted to be connected to a wedge-shaped cam, also not shown, similar to the cam 70 shown in Fig. 2.

While I have illustrated and described a preferred embodiment of the present invention, it will be understood, however, that various changes and modifications may be made in the details thereof without departing from the spirit and scope of the invention as set forth in the appended claims. Having thus described the invention, what I claim as new and desire to protect by Letters Patent is as follows:

1. In a temperature control mechanism for a liquid cooled engine, a shaft, a cooling fan secured to said shaft, a coolant liquid pump impeller also secured to said shaft, a rotary drive element journaled for free rotation relative to said shaft and adapted to be driven from the engine upon which said mechanism is mounted, radially movable clutch means mounted to rotate with said shaft for providing releasable driving connection between said engine driven element and said shaft, means normally urging the clutch means radially to released position free from the rotary drive element, and thermostatic control means exposed to temperature changes of coolant liquid, and operatively connected to actuate said clutch means radially into engagement with the rotary drive element on the attainment of a predetermined minimum coolant liquid temperature by said thermostatic control means to rotate said shaft, said impeller, said fan and said clutch means with said rotary drive element.

2. Mechanism for controlling the operation of the cooling fan and coolant circulating pump of a liquid cooled engine; said mechanism comprising a pump housing, a shaft mounted for rotation therein, a pump impeller secured to said shaft for rotation therewith within said housing, a cooling fan assembly secured to said shaft for rotation therewith exteriorly of said pump housing, a pulley journalled coaxially of said shaft for free rotation relative to said shaft, said impeller and said fan, a clutch mounted to rotate with said shaft and movable from a position clear of the pulley to a position frictionally engaging the pulley to establish releasable clutch engagement therewith, biasing means urging the clutch toward its position clear of the pulley, and thermostatically actuated means exposed to temperature changes of engine coolant liquid and operatively connected to move said clutch into frictional engagement with the pulley on the attainment of a predetermined temperature of coolant liquid.

3. Mechanism for facilitating the heating of a cold, liquid cooled engine; said mechanism comprising a pump housing, a shaft mounted for rotation therein, a pump impeller secured to said shaft for rotation within said housing, a cooling fan assembly secured to said shaft for rotation exteriorly of said housing, a pulley mounted for rotation relative to, and co-axially of, said shaft, clutch means carried by said fan assembly and adapted to have clutch engagement with said pulley, means normally retaining the clutch means out of clutch engagement with said pulley, and thermostatically actuated means exposed to engine coolant liquid and operatively connected to said clutch means to actuate said clutch means on the attainment of a predetermined temperature by said thermostatically actuated means.

4. Mechanism for rapidly increasing the coolant temperature upon starting a cold, liquid cooled engine; said mechanism comprising a pump housing, a pump impeller mounted for rotation within said housing, a fan assembly mounted exteriorly of said pump housing, and constructed and arranged to rotate co-axially with said impeller, an engine driven member mounted for rotation concentrically of said rotor and fan assembly and independently thereof, clutch means mounted on said fan assembly to rotate therewith, said clutch means being adapted to have releasable clutch engagement with said engine driven member, a clutch actuating member mounted for slidable movement radially of the axis of impeller and fan rotation, a portion of said clutch actuating member being positioned to engage said clutch means, cam means mounted to engage said clutch actuating member, and a thermostatic element exposed to the coolant liquid and connected to operate said cam means to move the clutch actuating member to clutch operating position upon a predetermined increase in temperature of said thermostatic element.

5. Mechanism for causing a rapid initial increase in coolant temperature upon starting a cold, liquid cooled engine; said mechanism comprising a liquid pump rotor, an engine cooling fan mounted co-axially of the pump rotor and connected to rotate therewith, an engine driven member mounted for rotation independently of the fluid circulating element, clutch means mounted to rotate with said pump rotor and fan, means biasing said clutch means toward released condition, said clutch means being mounted for movement by centrifugal force upon rotation of the pump rotor and fan toward clutch engagement with said engine driven member, and a thermostatically controlled element responsive to temperature changes in the coolant liquid and mounted to move said clutch means to engage said engine driven member upon a predetermined increase in coolant liquid temperature.

6. Mechanism for causing a rapid initial increase in coolant temperature upon starting a cold, liquid cooled engine; said mechanism comprising a liquid pump rotor, an engine cooling fan in driven relation with the pump rotor, an engine driven member mounted for rotation independently of the pump rotor and fan, a clutch element pivotally mounted in unbalanced condition coaxially of said pump rotor, to be urged by centrifugal force upon rotation of the pump rotor and fan toward driven relation with the engine driven member, means normally biasing said clutch element toward releasing condition, and means controlled by the temperature of the engine coolant liquid and mounted to move the clutch to engaging position upon a predetermined increase in temperature of said temperature controlled element, thereby to cause rotation of the pump rotor, fan and clutch element.

7. Mechanism for causing a rapid initial increase in coolant temperature upon starting a cold, liquid cooled engine; said mechanism comprising a pump housing, a pump impeller mounted for rotation within said housing, an engine driven member having a recess therein and mounted for rotation concentrically of said impeller and independently thereof, a fan assembly mounted exteriorly of said pump housing to rotate with said impeller, said fan assembly having a portion thereof forming a closure for the recess in said engine driven member, clutch means mounted on said impeller and fan assembly to rotate therewith within the recess in said engine driven member, said clutch means being adapted to have releasable clutch engagement with said engine driven member, and a thermostatically controlled element responsive to temperature changes in the coolant liquid, and constructed and arranged to move said clutch means to engage said engine driven member upon a predetermined increase in coolant liquid temperature.

References Cited in the file of this patent UNITED STATES PATENTS 1,233,518 Snyder July 17, 1917 1,566,272 Costa Dec. 22, 1925 1,594,259 Hardman July 27, 1926 1,684,601 Shpater Sept. 18, 1928 1,921,042 Roos Aug. 8, 1933 2,045,870 Paton June 30, 1936 2,452,264 Russell Oct. 26, 1948 2,551,662 Findley May 8, 1951 2,652,816 Dodge Sept. 22, 1953

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