US3675631A

US3675631A - Adjustable cam follower

Info

Publication number: US3675631A
Application number: US43037A
Authority: US
Inventors: William J Hixson
Original assignee: Individual
Current assignee: Individual
Priority date: 1970-06-03
Filing date: 1970-06-03
Publication date: 1972-07-11
Anticipated expiration: 1989-07-11

Abstract

A preferred form of follower includes an inverted cup-shaped body that fits over a valve stem of an overhead cam engine and includes a threaded central bore which receives a threaded plug. The bottom surface of the plug engages the valve stem and the top of the plug is provided with a square bore. A cap fits over the body and plug and is provided with a downwardly depending square boss that is fitted into the bore of the plug. The cap is provided with slots engageable by a screwdriver to rotate the cap and thus screw the plug axially inward or outward of the body to adjust the clearance between the cam and the valve stem. A plurality of circumferentially spaced locking holes are provided to be selectively engaged by a pin depending downwardly from the cap. A second form of the invention includes an inverted cupshaped body having an upwardly extending threaded boss. A cap overlies the body and is provided with a mating threaded bore. A recess is provided in the cap for rotating the cap and providing access to a set screw inserted through the cap for locking engagement with the threaded boss.

Description

United States Patent [151 3,675,631 Hixson 1 July 11, 1972 [$4] ADJUSTABLE CAM FOLLOWER [72] Inventor: William J. Hixson, 4220 NE. 90th St.,

Seattle, Wash. 98155 [22] Filed: June 3, 1970 [21] Appl. No.: 43,037

[52] U.S. C1 ..123/90.52, 123/9027, 74/55, 74/569, 74/586 [51] Int. Cl ..F0ll l/20,Fl6h 53/06 [58] Field of Search ..123/90.27, 90.52; 74/55, 569, 74/586 [56] References Cited UNITED STATES PATENTS 1,496,497 6/1924 Swarthout et a1 ..l23/90.52 X 1,443,715 1/1923 Petaza ..l23/90.52 3,002,508 10/1961 Barker et al, ...................123190.27 X 1,746,802 2/1930 Small .l23/90.52 X 3,002,509 10/1961 Fitzgerald et al. 1 23/9052 3,413,964 12/1968 Pask 123/9052 3,301,239 1/1967 Thauer.. ..l23/90.52 3,538,895 11/1970 Jensen ..123/90.27

Primary Examiner-Al Lawrence Smith Attorney-Seed, Berry & Dowrey ABSTRACT A preferred form of follower includes an inverted cup-shaped body that fits over a valve stem of an overhead cam engine and includes a threaded central bore which receives a threaded plug. The bottom surface of the plug engages the valve stem and the top of the plug is provided with a square bore. A cap fits over the body and plug and is provided with a downwardly depending square boss that is fitted into the bore of the plug. The cap is provided with slots engageable by a screwdriver to rotate the cap and thus screw the plug axially inward or outward of the body to adjust the clearance between the cam and the valve stem. A plurality of circumferentially spaced locking holes are provided to be selectively engaged by a pin depending downwardly from the cap. A second form of the invention includes an inverted cup-shaped body having an upwardly extending threaded boss. A cap overlies the body and is provided with a mating threaded bore. A recess is provided in the cap for rotating the cap and providing access to a set screw inserted through the cap for locking engagement with the threaded boss.

6 Claims, 3 Drawing Figures P'A'TENTEDJuL n 1912 3.675.631

re in 7// A l l d WILLIAM J. HIXSON INVENTOR.

ATTORNEYS ADJUSTABLE CAM FOLLOWER BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to cam followers of the type wherein the cam shaft is located directly over and in close proximity to the valve stem.

2. Description of the Prior Art One difficulty imposed by the use of overhead type cam shafts is that the space available to make adjustments in the follower to provide proper valve clearance is very limited. In some cases the follower is almost completely submerged in a sleeve or in the engine head such that it is impossible to approach the follower from the side to make adjustments. One technique to solving this problem is to use special tools to make the adjustment and/or cut special bores in the cam shaft to allow access to the follower from above the shaft, as taught, for example, in the patent to Thauer US. Pat. No. 3,301,239. Another technique has been to design the follower so that it extends upwardly from the sleeve or engine head a sufficient distance to permit access with adjustment tools brought in from the side. Such a technique is shown, for example. in the patents to Fitzgerald et al. US. Pat. No. 3,002,509 and Barker et al. US. Pat. No. 3,002,508.

SUMMARY OF THE INVENTION This invention pertains to an adjustable cam follower that may be approached directly from above when making adjustments in the valve clearance. In the preferred form the follower includes two members rotatable relative to one another and a third member movable longitudinally of the first two members in response to said relative rotation. In this form of device the locking and adjusting operation is accomplished within a space as narrow as 0.310 inches. Conventional tools, such as screwdrivers, may be used to make the adjustment and once made the first two members will automatically be locked together to prevent longitudinal movement of the third member which would otherwise accidentally change the valve clearance setting. Since only three major parts are included the manufacturing and assembling costs are minimized. Furthermore, with this type of follower the other parts of the engine, such as the cam shaft, need not have special features to allow for adjustment of the follower.

The second embodiment includes two members one threaded on the other which may also be adjusted from above without the need of special tools.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is an axial section of the preferred form of adjustable follower of this invention.

FIG. 2 is a transverse section taken along the lines 2-2 of FIG. 1.

FIG. 3 is an axial section of the second form of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT The preferred embodiment, shown in FIGS. 1 and 2, cmploys an inverted cup-shaped body having depending cylindrical side walls 12 and an upstanding peripheral shoulder 14. The body is provided with a central threaded bore 16 in which is received a threaded plug 18. The bottom surface of the plug is smooth and engages the top of a conventional valve stem 20. The top end of the plug is provided with a square bore 24.

A cap 26 is seated in the recess within the peripheral shoulder 14 of the body 10 and is provided with a central, downwardly depending, square boss 26 slidably engaged in the square bore 24. A locking pin 28 depends downwardly from the cap 26 and is engageable within one of a plurality of circumferentially spaced locking holes 30 in the top surface of the body 10. A plurality of notches 32 each having inclined top and bottom walls are provided in the top surface of a cap 26. The notches are of a size suitable for penetration by the tip of a screwdriver so that the cap may be lifted and rotated. The length of the square boss 26 is greater than that of the pin 28. Thus the cap may be raised to disengage the pin from a locking hole 30 to permit relative rotation between the cap and the body while still maintaining contact between the square boss 26 and the square bore 24.

To operate the cam follower of the preferred embodiment the shoulder 14 of the body 10 is pressed downwardly to release the cap from engagement with the cam shaft. Next, a screwdriver is placed in one of the notches 32 and the cap is lifted to disengage the locking pin 28 from the locking hole 30. Next, the cap is rotated and, since the square boss 26 is still engaging the square bore 24, the plug 18 is screwed to move axially relative to the cap and body. Downward axial move ment of the plug decreases the clearance whereas upward movement of the plug increases the clearance. The cam is locked to the body by lowering the cap and inserting the locking pin into one of the locking holes on the cap.

In the modification shown in FIG. 3 the follower includes an inverted cup-shaped body 50 having a depending cylindrical side wall 52 and a downwardly depending boss 56 which engages the valve stem 58. The body 50 also includes an upstanding threaded boss 58. A cap 60 fits over the body 50 and includes a central threaded bore 62 which receives the threaded boss 58. Thus relative rotation of the cap and body will cause relative axial movement between the two to provide for valve clearance adjustment. The cap is also provided with a recess 64 which terminates in an inclined threaded bore 68 that intersects the threaded bore 62. A set screw 70 is threaded into the inclined bore 68 and when threaded into engagement with the threads on the boss 58 will preclude relative rotation between the cap and the body.

In this form of follower the valve clearance adjustment is made by loosening the set screw 68 and then rotating the cap 60 relative to the body 50 by using a screwdriver or the like in the recess 64. When the desired clearance is obtained the set screw 70 is then screwed into engagement with the threads on the boss 58.

While preferred nonlimited forms of the invention have been described modifications will be readily apparent to those skilled in the art.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

I. An adjustable cam follower comprising an inverted cupshaped body with an open end embracing a valve stem and having a threaded central bore; a plug threaded into said bore; a cap overlying said plug and said body; means slidably interconnecting said cap and plug for rotation of said plug with said cap thereby raising or lowering said plug relative to said body while permitting relative axial movement between said cap and said plug; means for rotating said cap; and means for releasably locking said cap and said body against relative rotation when in a normal operating condition.

2. The follower defined by claim I wherein said slidable interconnecting means includes a square bore in said plug and a square boss on said cap depending into said square bore.

3. The follower defined by claim 2 wherein said releasable locking means includes at least one locking hole in said body and a locking pin on said cap, said boss being of a length sufficient to be engaged in said square bore when said locking pin is disengaged from said locking hole whereby the cap and plug are rotatable together relative to said body by lifting said cap to disengage said locking pin.

4. The follower of claim 3 wherein said body includes a plurality of circumferentially spaced locking holes.

5. The follower defined by claim 1 wherein said cap includes a top surface and said means for rotating said cap includes a plurality of notches each of which includes inclined top and bottom walls adapted to be engaged by a tool for simultaneously lifting and rotating said cap.

6. The follower of claim 4 wherein said cap includes a top surface and said means for rotating said cap includes a plurality of notches each of which includes inclined top and bottom walls adapted to be engaged by a tool for simultaneously liftin; and rotating said cap.

I ll t III

Claims

1. An adjustable cam follower comprising an inverted cup-shaped body with an open end embracing a valve stem and having a threaded central bore; a plug threaded into said bore; a cap overlying said plug and said body; means slidably interconnecting said cap and plug for rotation of said plug with said cap thereby raising or lowering said plug relative to said body while permitting relative axial movement between said cap and said plug; means for rotating said cap; and means for releasably locking said cap and said body against relative rotation when in a normal operating condition.

2. The follower defined by claim 1 wherein said slidable interconnecting means includes a square bore in said plug and a square boss on said cap depending into said square bore.

6. The follower of claim 4 wherein said cap includes a top surface and said means for rotating said cap includes a plurality of notches each of which includes inclined top and bottom walls adapted to be engaged by a tool for simultaneously lifting and rotating said cap.