TREA

Freeze plug

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Information

  • Patent Grant
  • 4930459
  • Patent Number
    4,930,459
  • Date Filed
    Friday, July 21, 1989
    35 years ago
  • Date Issued
    Tuesday, June 5, 1990
    34 years ago
Information
Abstract
A cup-shaped freeze plug for a coolant hole in an engine block. The plug includes a base section having a diameter less than the hole's nominal diameter, the base diameter being sized to permit the plug to be hand-fitted into the coolant hole at an intermediate non-sealing position. The plug also includes a rim section formed integral with the base section, the rim section having a diameter greater than the hole's nominal diameter, the rim diameter being sized to allow the plug to be force-fitted into the coolant hole at a final coolant sealing position.
Description
Claims
  • 1. A method of installing a freeze plug in a coolant hole for an engine block, said method comprising the steps of
  • providing a cup-shaped freeze plug having a base section of a minor outside diameter which is less than the nominal diameter of said hole, and a rim section of a major outside diameter which is greater than the nominal diameter of said hole,
  • preliminarily fitting said freeze plug's base section into said hole by hand in a non-sealing position in order to properly orient and locate said freeze plug in said hole, and
  • thereafter force fitting said freeze plug's rim section into said hole by driving said rim section into a coolant sealing position therein.
  • 2. A method as set forth in claim 1,
  • said cup-shaped freeze plug having a base diameter between about 0.2% and about 0.8% less than said nominal diameter, and said rim section having a rim diameter of between about 0.7% and about 0.9% greater than said nominal diameter.
  • 3. A method as set forth in claim 2,
  • said base section having a depth of between about 50% and about 70% of the overall depth of said plug, and said rim section having a depth of between about 30% and about 50% of the overall depth of said plug.
  • 4. An engine block assembly for use in a motor vehicle, said assembly comprising
  • an engine block having a coolant hole, said hole having a nominal diameter, and
  • a freeze plug sealingly fitted in said coolant hole, said plug comprising
  • a base section having an outside diameter less than said nominal diameter, said base diameter being sized to permit said plug to be hand-fitted into said coolant hole at an intermediate non-sealing position, and
  • a rim section formed integral with said base section, said rim section having an outside diameter greater than said nominal diameter, said rim diameter being sized to allow said plug to be force-fitted into said coolant hole at a final coolant sealing position.
  • 5. An assembly as set forth in claim 4,
  • said base diameter being between about 0.2% and about 0.8% less than said nominal diameter, and
  • said base section having a depth of between about 50% and about 70% of the overall depth of said plug, and
  • said rim diameter being between about 0.7% and about 0.9% greater than said nominal diameter, and said rim section having a depth of between about 30% and about 50% of the overall depth of said plug.
Parent Case Info

This invention relates to freeze plugs. More particularly, this invention relates to freeze plugs of the type adapted to be used with engine blocks. A cup-shaped freeze plug is often used with an engine block of a liquid cooled internal combustion engine. This is particularly true of those engines used in over-the-road motor vehicles, e.g., automobiles, trucks and buses. The freeze plug operates to stop up a hole in the engine block which opens into the block's coolant channel. The objective of the freeze plug is to protect the engine block, i.e., to keep the engine block from cracking, in the event the liquid coolant freezes in cold weather. Specifically, and when the system operates correctly, the freeze plug functions to pop out of the engine block's hole, instead of the engine block cracking, when the liquid coolant in the engine expands upon freezing. The freeze plug functions in this manner because the plug itself is sized and fitted into the engine block's hole so it takes less coolant expansion pressure to pop the plug out than to crack the block. There is one problem of significance with cup-shaped freeze plugs which I am familiar with, and that are commercially used today. The freeze plug is press-fitted in the engine block's hole to provide a non-leaking friction fit seal. This press fit obviously must be a very tight friction fit since in use the freeze plug prevents coolant from exhausting out of the engine block's hole, and since the objective is to have the plug pop out so as to prevent the block from cracking if the coolant within the block freezes. Now with prior art freeze plugs of which I am aware, and which are of the cup-shaped type, the prior art plug tends to roll around in the engine block's bore as an effort is made to drive it into its final press-fit sealing position within the bore. In other words, when a mechanic tries to drive the separate cup-shaped freeze plug into the engine block's bore with a punch or hammer, it is difficult to get the plug started in straight in the first place. And if the freeze plug is not put in straight, or if its side walls are nicked or gouged as it is put in, then in the second place liquid coolant tends to leak out of the engine's block bore as the engine is used. Quite obviously, coolant leakage from an engine block's coolant system is undesirable. Therefor, it has been the objective of this invention to provide an improved cup-shaped freeze plug for a coolant hole in an engine block where the freeze plug can be preliminarily set into an intermediate position within the block's hole by hand, and where thereafter the freeze plug can be driven into tight fitting sealed relation with the bore by a mechanic, thereby minimizing the use difficulties with prior art freeze plugs as discussed above. In accord with this objective, this invention contemplates a cup-shaped freeze plug for a coolant hole in an engine block. The plug includes a base section having a diameter less than the hole's nominal diameter, the base diameter being sized to permit the plug to be hand-fitted into the coolant hole at an intermediate non-sealing position. The plug also includes a rim section formed integral with the base section, the rim section having a diameter greater than the hole's nominal diameter, the rim diameter being sized to allow the plug to be force-fitted into the coolant hole at a final coolant sealing position.

US Referenced Citations (8)
Number Name Date Kind
397839 Dodge Feb 1889
787460 Mosher Apr 1905
1492248 Hachmann Apr 1924
1710363 Kramer Apr 1929
1888319 Hopkins Nov 1932
3333723 Wisman Aug 1967
3889841 Edmonds Jun 1975
4750457 Bonutti Jun 1988