US2406817A - Hammer slot and floating pin assembly for automatic push rods - Google Patents

Description

P 1946 H. H. ENGEMANN 06,817 HAMMER SLOT AND FLOATING PIN ASSEMBLY FOR AUTOMATIC PUSH RODS Filed June 2, 1944 1 2 70 I Her Earl hf p'gei nann. M I 5' Patented Sept. 3, 1946 HAMMER SLOT AND FLOATING PIN AS- SEMBLY FOR AUTOMATIC PUSH RODS Herbert H. Engemann, Cleveland Heights, Ohio Application June 2, 1944, Serial No. 538,455

This invention relates to automatically extensible and contractable links for providing a constant predetermined adjustment in the valve-operating linkage of an internal combustionengine.

Specifically the invention relates to the inertia hammer and pin arrangement of automatic push rods.

According to this invention an automatically extensible and contractable rod or link is incorporated in the operating mechanism between the cam shaft and poppet valve of an internal combustion engine to maintain a desired amount of operating clearance in the assembly irrespective of temperature variations in the engine and Wear of parts which change clearance relationships in such assemblies. The push rods or links of this invention include threaded-together male and female parts with a torsion spring acting to rotate the parts in one direction for lengthening the assembly together with an inertia ham- 8 Claims. (Cl. 123--90) mer effective to rotate the parts in the reverse direction for shortening the assembly.

During the upstroke, or valve-opening stroke of the push rods of this invention, the rods are under compression load and act as rigid members for transmitting movement. Duringthis upstroke the push rod is decelerated at about half open valve position and inertia causes a telescoping sleeve or inertia hammer to fly upwardly on the rod. On the downstroke, the rod is decelerated at about half closed valve position and the inertia hammer flies downwardly to hit a 1'0- tative impact blow on a pin carried in one of the threaded parts for rotating this part in one direction against the bias of the torsion spring to shorten the length of the rod. Immediately after the hammer energy is spent, the torsion spring unwinds and rotates the part in the reverse direction to lengthen the rod and take all undesired play out of the linkage. This is done before the next valve opening cycle. 7

In order to ermit the valveto be seated when the rod has been elongated to compensate for heat expansion of the engine and when the engine has then been stopped and cooleddown, a s ring-pressed valve-operating clearance arrangement is provided. This spring-pressed arran ement is weaker than the valve spring but stronger than the torsion spring so that the valve can remain closed even though the rod is actually too long to permit this closure.

Difiicultv has been experienced in devices of the type referred to because of unauthorized driving rotation imparted by the inertia hammer, on the upstroke of the rod when the rod should act as a rigid member. According to this invention such driving rotation on the upstroke is either entirely eliminated or reduced to a negligible amount by controlling the impact angles of the hammer relative to the impact pin. Such control is accomplished by curving the slots of the hammer in which rides a floating pin. The floating pin cannot bind or otherwise interfere with free actuation of the assembly.

It is, then, an object of this invention to provide automatically extensible and contractable devices wherein contraction is obtained by action of an inertia sleeve or hammer on a floating pin.

A still further object of the invention is to provide an inertia hammer and pin assembly for automatic push rods which imparts an efiicient rotative blow only after the valve actuated by the push rod is completely closed.

Another object of the invention is to provide an inertia sleeve or hammer for automatic push rods with a slot arrangement which drives an impact blow in a rotary direction only on the downstroke of the rod.

A still further object of the invention is to provide a slot arrangement for inertia hammers of push rods'which relieves oil to insure a full impact force. A

A still further object of the invention is to pro-i vide a floating in assembly for automatic push rods which cannot bind, work loose, or in any way interfere with free operation of the assembly,

Other and further objects of theinvention will be apparent to those skllled in the art from the following detailed description of the annexed sheet of drawings which, by way of preferred example only, illustrate two embodiments of the invention.

On the drawing:

Figure 1 is a fragmentary broken side elevational view, with parts in vertical cross section, of a push rod assembly according to this invention.

Figure 2 is an enlarged fragmentary broken vertical cross-sectional view of parts of the push rod of Figure 1, taken along the line II-II of Figure 3.

Figure 3 is an enlarged side elevational view of the lower portion of the push rod of Figures 1 and 2.

Figure 4 is enlarged vertical cross-sectional view of another form of push rod or automatic tappet according to this invention.

Figure is a fragmentary cross-sectional view taken along the line VV of Figure 4.

As shown on the drawing:

In Figure 1 thereference numeral l0 designates generally an en ine body having a bore II therein in which is slid-ably seated a hollow cam follower l2 havin a bottom wall [2a acted upon by a cam 13 of a cam shaft H. The side wall l2b of the cam follower rides in the bore H of the engine body and has an aperture l5 therein adapted to be aligned with an oil supply duct It in the engine body.

A cup I! is seated in the open top end of the cam follower l2 and has a shoulder Ha bottomed on top of the cam follower. The ball cup H has an aperture llb in the bottom thereof adapted to receive oil from the interior of the cam follower l2. A fragmental ball seat lie" is provided in the ball cup H.

A push rod 88 has a bottom stud IS with a segmental ball end l9a rockably and rotatably mounted on the ball seat Il'c of the cup ii.

The push rod it has an elongated internally threaded nut 28 mounted in the lower end of a tube 2! and having a shoulder 29a thrusting on the bottom end of the tube 2i. The stud l9, as shown in Figures 1 and 2, has an enlarged cylindrical portion i517 spaced beneath the nut and tube 21, together with a threaded shank portion 580 which is threaded into the nut 20.

The stud It has an axial bore I9d therethrough together with a transverse bore We in the enlarged portion 92) thereof intersecting the bore IM.

A pin 22 is passed through the transverse bore Me. This pin hasa free fit in the bore 19c.

The ends of the pin project into" the slots 23, 23 of an impact hammer or sleeve 24 which is slidably mounted on the lower portion of the tube 2! and on the cylindrical portion E911 of the stud.

The pin 22 has an annular groove 2320. around the central portion thereof disposed in the bore Esd. A hollow plunger 25 is seated in the bore Mid and bottomed in the groove 22a. A spring 26 in the bore ltd acts on the plunger 25 to urge it into the groove 22a.

The top portion of the bore "id is internally threaded and receives, in threaded relation therein, a bushing 2?. The bushing 2'! acts on the top of the spring 26 to hold the same under compression. The bushing 27 has a head 21a bottomed on top of the shank portion I90 of the stud IS.

A rod 28 is anchored in the bushing 2? and projects upwardly therefrom through the central portionof the tube 21. The upper end of the rod 28 carries a spring anchor 29 also encased by the tube 2|. A torsion spring 30 (Fig. 1) is anchored at one end 30a. thereof to the nut 28 and at the other end 30b thereof to the anchor 29. The torsion spring acts to reversely rotate the stud l9 and nut 20 in an unscrewing direction to elongate the stud and nut assembly.

The upper end of the rod 2|, as shown in Figure 1, carries a stud 3| having a ball end 3m,

seated in a ball cup 32 carried by the rocker arm 33 of the valve linkage. The stud may be spring-pressed as is described in my copending application S. N. 538,454.

An operating clearance space C is provided between a shoulder 3 lb of the stud 3i and the top of the rod. The arrangement as described inthe above mentioned copending application is such that this clearance space C can be adjusted to provide any desired gap and, on the upstroke of the rod !8, the spring holding the poppet valve (not shown) in closed position is stronger than the spring acting on the stud 3! so that the space C will be taken up before the push rod is effective to rock the arm 33.

On the valve-opening stroke, or upstroke of the assembly, the cam iii of the cam shaft I iraises the cam follower :2 which cam follower, in turn, raises the push rod I8 to take up the clearance space C and then cause the stud 3| to rock the arm 33. During about the last half portion of the upstroke the push rod is decelerated and the inertia hammer or sleeve 2 flies upwardly to receive the pin 22 in the bottoms 23a of its slots 23 (Fig. 3). As shown in Figure 3, the slot 23 is arranged so that upward movement of the sleeve 24 on the pin 22 will not cause any rotative throw to be delivered on the pin since the bottom portion of the slot 23 is vertical. However, the slot curves from a vertical bottom 23a to an inclined top 23b.

When the cam l3 allows the cam follower 2 to drop, the push rod is accelerated on its downstroke to about half closed valve position and is then decelerated as the cam contour slows up the rod to a stop at fully closed valve position. However the hammer 24 is free to fly downwardly at the maximum downwardspeed attained by the rod before deceleration by the cam. This downward movement of the sleeve 24 is accompanied by a rotative movement of the sleeve caused by the curved slots 23 and when the inclined tops 23b of the slots impact the pin, they deliver a rotative blow to this pin. Since the pin is seated in the stud t9 rotation of the pin will rotate the stud. The slots 23 are curved in such a direction that this rotative action on the stud will be in a direction to thread the Stud [9 into the nut 20, thereby shortening the efiective length of the rod and. winding up'the torsion spring 30. Immediately after the hammer energy is spent in this way the torsion spring has ample time to unwind thereby reversely rotating the stud l9 and lengthending the rod 18 before the next valve opening cycle.

The torsion spring 30 thus automatically removes any undesi-rable play in the valve linkage but the spring is too weak to compress the spring which maintains the operating clearance space C between shoulder 31b and the top end of the rod 2! which spring. is shown in the above mentioned copending application. However should the spacing C become less than the intended operating clearance, due to thermal changes in the engine, then the inertia hammer 2t becomes effective to shorten the push rod until the desired clearance space C isre-established.

Oil to. lubricate the rod assembly can be fed from the oil. duct. [5 through the aperture $5 in the cam follower I 2 and thence through the open.- ing Hb in the ball cup ll into the axial bore Hid of the stud 19. One. or more radial oil holes 34 (Fig. 2) are provided. in the threaded portion lilo of'the stud to supply oil from the bore Hid to grooves such as 35 in the threaded exterior of the stud. These grooves distribute oil to the threads and to grooves 36 which are open at the bottom ends 36a thereof above the enlarged portion 19b of the stud l9. Oil can thus drain through the grooves 36 for lubricating the bearing surfaces for the sleeve 24, via, the tube 2| and enlarged portion |9b of the stud [9.

In order toprevent oil from being trapped between the pin 22 and the upper ends 232) of the slots 23, the upper ends of the slots are relieved as at 230 (Fig. 3) on each side of the pin 22 so that any oil between the pin. and the slot wall 23b can be readily forced into: the relieved portions 23c thereby permitting the full impact blow of the sleeve on the pin.

Since the pin 22 has a free fit in the bore We of the. stud [9. expansion and contraction of the bore due to varying temperatures of the assembly will not afiect the pin because the pin is floating in the bore. At the same time, however, the pin is held against endwise movement so that its ends will always extend into the slots 23 cf the sleeve '24 by the spring-pressed plunger '25 act position and is not affected by vibration or by temperature changes.

In the embodiment shown in Figures 4 and 5, a push rod or tappet 40 has a hollow cylindrical housing 4| with a bottom wall 4|a adapted to be acted on by a cam of a cam shaft (not shown) and with a side wall 4| b adapted to slide in the bore of an engine body member (not shown). The side wall has an aperture 4|c therein to receive lubricant from the engine body in the manner shown in Figure l.

The open top of the housing 4| receives a nut 42 with a head 42a bottomed on top of the housing. A stud 43 is threaded through the nut 42 and the stud and nut are provided with conventional threads such as V-threads. The lower end of the threaded portion of the stud 43. has several turns of truncated threads 44a thereon. These threads have fiat tops and cooperatewith the adjacent V-threads of the stud 43 to provide a shoulder or stop 45. A spring anchor 46 is threaded on the truncated threads 440. against the stop 45.

A torsion spring 41 is anchored at one end 4m to the nut 42 and at the other end 411) to the anchor 46. This torsion spring is effective to rotate the anchor 45 tightly against the shoulder 45 of the stud and then rotate the stud 43 in 1 the nut 42 until the anchor 46 abuts the nut 42 as shown in Figure 4. In operating position, the tappet assembly as shown in Figure 4 is so installed in the valve linkage that there is a slight spacing between nut 42 and anchor 46. Thus, the torsion spring 41, like the spring 30 in the modification of Figure 1, tends to lengthen the assembly by rotating the stud in a direction to screw it outwardly from housing 4|.

The lower end of the stud 43 projects beyond the anchor 46 and has diametrically opposed transverse circular holes 48 therethrough receiving a pin 49 freely therein. The pin49 projects through the slots 50a, 50a of an inertia hammer 50, and the ends of the pin are adapted to ride on the cylindrical inner wall 4|c of the housing 4|. The hammer sleeve 5|] has outwardly pressed bead portions 501) at the top and bottom thereof for sliding on the cylindrical inner wall Me of the housing 4|.

The slots 50a of the sleeves 50 are similar to the slots 23 of the sleeve 24 and have bottom ends extending in vertical directions and top ends extending in inclined directions together with relieved portions 50c on each side of the pin 49 to receive oil and. prevent an oil trap.

The vibratory action of the sleeve 50 is such that on the downstroke of the assembly it will deliver a rotative blow to the pin 49 rotating the stud 43 against the action of the torsion spring to foreshorten the assembly. The torsion spring lengthens the assembly by screwing the stud in an outward direction from the nut.

A cap 52 is threaded on the upper end of the stud 43 and slidably supports a valve-actuating seat 53. A look nut 54 is provided under the cap 52. The support 53 is spring-pressed by means of a coil spring 55 held under compression between the pin 49 and the seat 53 and extending through the hollow stud 43. An operating clearance C is provided between the member 53 and the top of the stud. This operating clearance C' provides a safety arrangement under conditions where due to sudden thermal changes and especially at low engine speeds the impact hammer is unable to shorten the effective length of the valve linkage fast enough to keep up with the thermal. changes. Under this condition, the preset clearance C will be slightly diminished for a short period, until the impact hammer, by means of rotative impacts on pin49, has'screwed stud 43 into nut 42 in a shortening direction sufficiently until the pre-set clearance at C is reestablished. Through this operating clearance C, therefore, the valve is permitted to seat properly at all times.

The assembly 40 operates thesame as the assembly I8, and can be used in installations not involving rocker arms, since the member 53 can act directly on a valve stem or a member seated on the valve stem.

From the above descriptions it will be understood that the invention now provides a slot and. pin arrangement for automatic push rods which translates inertia forces of a sliding sleeve in a vibratory linkage into rotative movements for resisting a torsion spring to foreshorten a link or push rod.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. An extensible and contractable link member comprising threaded-together male and female members, a torsion spring reversely rotatin said members for lengthening the link, an inertia hammer freely slidable on said link having diametrically opposed slots with substantially vertical first ends and inclined second ends, a pin freely carried by one of said threaded-together members projecting into said slots, and means holding said pin in assembled relation whereby movement of the sleeve in one direction will impart an axial impact on the pin while movement of the sleeve in the reverse direction will cause a rotative impact on the pin resisting said torsion spring to thread the male and female members together for shortening the link.

2. An extensible and contractabl'e link assembly comprising threaded-together male and femal parts, spring means acting on said parts to lengthen the assembly, an inertia hammer movable relative to said assembly, a pin loosely mounted in said one part, said hammer having a slot engageable by said pin, resilient means for positioning said pin in engagement with said slot, said slot having one end substantially parallel to the path of movement of said hammer and another end inclined to the path of movement of said hammer, whereby relative rotation of said male and female parts to shorten the assembly is produced by only one direction of movement of said hammer.

3. In a vibratory mechanical linkage, a link member having threaded-together parts, a torsion spring rotating the parts for lengthening the link member, a pin loosely mounted in by one of the parts, means holding the pin against endwise movement, and inertia weight movable relative to said link member and having slots receiving the ends of the pin, said slot being constructed and arrangedto impart a longitudinal blow. on thetpih during one. stroke of the linkage and a rotativeiblowi on the opposite stroke of the linkage whereby the parts will beythreaded together by the rotative blow to shorten the link.

4. An automatic push rod including a nut, a holoww stud threaded; into said nut, a torsion spring reversely rotating the stud and nut to lengthen the push rod, a pin extending freely through. said stud,. a spring-pressed plunger in said stud. acting on said pin to hold. the same against endwise movement, and an inertia weight having slots receiving the ends of the pin arranged ior delivering a rotative impact blow to the pin on one stroke of the push rod. and a longitudinal blow on the pin on the opposed stroke of the push rod.

5.. A pus-1i rodfor valve linkages of internal combustion. engines which comprises hollow threaded-together male and female members, a torsion spring for rotating said members relative to each other to lengthen the push rod, a pin extending transversely through the hollow male member and having a centrally grooved portion, asp'ri-ng-p'resse'd plunger in the hollow male member seated in said grooved portion of the pin to hold the pin against endwise movement, an inertia hammer slidable on the push rod having opposed slots receiving the ends of the pin, and said slots being arranged with vertical lower ends and inclined upper ends to deliver longitudinal blows to the pin on the upstroke of the push rod and rotative blows to the pin on the downstroke of the push rod.

6. An automatic push rod assembly for valve linkages comprising threaded-together male and female parts, a pin passed transversely through the male part, a sleeve slidable on the push rod having diametrically opposed slots receiving the ends of said pin, said slots having substantially vertical lower ends and inclined upper ends together with relieved portions at the upper ends whereby the sleeve will impart rotative impact blows to the pin on one stroke of the push rod.

'7. A push. rod assembly comprising threadedtogether male and female parts, a pin passed transversely through the male parts in free slidable relationship therewith, a hammer sleeve movable relative to said parts and having slots receiving the ends of the pin, a housing encasing said hammer sleeve and male part having interior walls for guiding the ends of the pin to hold the same in assembled relation, said slots in said hammer sleeve having one end thereof substantially parallel tothe path of movement of said hammer and the other end thereof inclined to the path of movement of said hammer, thereby delivering rotative impact blows to the pin for rotating the male member in only one direction by movement of said hammer.

8. In a linkage having cooperating male and female parts relatively rotatable to effect adjustment of the length of the linkage, the improvements of an inertia hammer movable relative to said parts and having a slot therein, a pin member engageab'fe in one of said parts and projectil'ig into said slot of said inertia hammer, at least one end of said slot being constructed and arranged to impart a rotative blow to said pin when said inertia hammer moves relative to said parts, the engaging surface of said one end of said slot having a plurality of recesses formed therein to provide lubricant receiving pockets during impact of the said end of said slot against said pin.

HERBERT H. ENGEMANN.

Images