US3321043A

US3321043A - Oil bath lubrication for mechanism

Info

Publication number: US3321043A
Application number: US354241A
Authority: US
Inventors: Jack S Vaughn
Original assignee: Ingersoll Rand Co
Current assignee: Ingersoll Rand Co
Priority date: 1964-03-24
Filing date: 1964-03-24
Publication date: 1967-05-23
Anticipated expiration: 1984-05-23

Description

May 23, 1967 J. s. VAUGHN OIL: BATH LUBRICATION FOR MECHANISM Filed March 24, 1964 INVENTOR. JACK 5. VAUGHN United States Patent 3,321,043 OIL BATH LUBRICATION FOR MECHANISM Jack S. Vaughn, Sayre, Pa., assignor to IngersolLRand Company, New York, N.Y., a corporation of New Jersey Filed Mar. 24, 1964, Ser. No. 354,241 Claims. (Cl. 184-1) This invention relates to mechanism lubrication and more particularly to oil bath lubrication for impact mecha- IllSIIlS.

Heretofore, in impact mechanisms utilizing lubricant bath lubrication, it was necessary to seal the motor means from the impact mechanism to prevent the lubricant from leaking into the motor means. Also the impact mechanism must be sealed at the anvil so the lubricant will not leak to the outside of the impact tool. The seal on the motor end has to be run at motor speed, which is very high. Under no load conditions the anvil will run approximately this same speed. Both seals are therefore vulnerable to overheating resulting in frequent failure of the seals.

It is the general object of the present invention to avoid and overcome the foregoing and other difficulties of and objections to prior art practices by the provision of an impact mechanism that will greatly reduce seal failure.

Another object of the present invention is to reduce the number of seals for an impact mechanism.

The aforesaid objects of the present invention, and other objects which will become apparent as the description proceeds, are achieved by providing an impact mechanism of the class wherein a hammer strikes an anvil to impart rotation to said anvil. The combination with the impact mechanism of reservoir means encasing the hammer mechanism to hold lubricating fluid. In addition the provision of seal means disposed on said anvil between the reservoir means and the anvil and rotating with the anvil to seal the lubricating fluid in the reservoir means.

For a better understanding of the present invention reference should be had to the accomanying drawings, wherein like numerals of reference indicate similar parts throughout the several views and wherein:

FIG. 1 is a longitudinal sectional view illustrating an impact mechanism;

FIG. 2 is a vertical sectional view taken along the line 2-2 of FIG. 1 in the direction of the arrows and illustrating the engaging and disengaging members of the impact mechanisms;

FIG. 3 is an enlarged sectional view of the seal shown in FIG. 1.

Although the principles of the present invention are broadly applicable to high speed mechanisms, the present invention is particularly adapted for use in conjunction with impact mechanisms and hence it has been so illustrated and will be so described.

With specific reference to the form of the present invention illustrated in the drawings, and referring particularly to FIG. 1, an impact wrench is indicated generally by the reference numeral 10. The impact wrench is of the standard type well known in the art having an anvil 12, disposed in a casing 13. The anvil 12 is provided at its working end 14- with a socket 16 capable of receiving a nut (not shown) which nut is to be driven into a work piece (not shown). A hammer frame 20 containing a hammer 18 is disposed around the anvil 12 in the casing 13. The hammer 18 oscillates about a hammer pin 22 to strike a dog 24 on the anvil 12 and thereby rotate the anvil 12. The hammer 18 is controllably rotated through a drive means, such as a rotor shaft 26 and cam 28 as shown in FIG. 1. It is understood that the rotor shaft is rotatably driven by any number of well known motor means such as an air motor (not shown) or an electric motor (not shown).

It will be understood by those skilled in the art that the hammer 18 can cause the anvil 12 to rotate at approximately the same speed as the motor under no load conditions. The anvil speed under load is the B.P.M. rate which is considerably less than the motor speed.

In order to provide constant and effective lubrication to the anvil 12 and hammer 18, fluid bath lubrication is utilized. Reservoir means, such as a can 36', is disposed in the casing 13, encasing the anvil 12, the hammer 18, the hammer frame 20 and the hammer pin 22, as shown in FIG. 1. As is apparent from the drawings, the pin 22 is fixed to the can 30 so that when the hammer l8 and hammer frame .20 rotate, the reservoir or can 30 also rotates at the same speed. When no load or a load below a predetermined minimum is applied to the anvil through the socket 16, the hammer 18, through the dog 24, will cause the anvil 12 to continuously rotate with the hammer and reservoir 30. When a load above the predetermined minimum is applied to the anvil as when the fastener to be tightened reaches a certain torque, the anvil stops rotating and the hammer swings away from the dog 24. When the hammer 18 is clear, the hammer makes one revolution relative to the anvil 12. As the hammer revolves about the anvil, the dog 24 swings the hammer back into a position to deliver an impact to the dog 24 and rotate the anvil 12 a certain amount. Thus, above the predetermined torque, the rotation of the anvil with the hammer and reservoir 36) becomes intermittent. The can 30 is supplied by a lubricating fluid, such as oil, through

ports

32 and 34 disposed on the can 30 and the casing 13 respectively. In order to prevent the lubricating fluid from leaking out of the can 30, seal means such as a dynamic seal 36 and a static seal 38 are provided.

The dynamic seal 36 is disposed between the can 30 and the anvil 1.2 and is attached to the circumference of the anvil 12 in order to rotate with the anvil 12.

The dynamic seal 36 comprises three friction seals 35a, 35b and 360 as shown in FIGS. 1 and 3. Two of the seals 36a and 36c fit in the can 30 (note the O ring touching the can 30 at X). The third seal 36b fits on the anvil 12 (note the O-ring touching the can 30 at Y). In addition the

seals

36a, 36b and 36c function as face seals and are in contact at point Z as shown in FIG. 1. The faces of the seals Sea, 36!) and sec are kept in contact by the urging action of a load spring 37 as shown in FIG. 3. The two O-rings X engage the can 3G to prevent fluid from leaking around the can and prevent rotation of the can 30 relative to the rings 36a and 360. The O-ring Y engages the anvil 12 to prevent leakage around the anvil and prevent rotation between the anvil and the ring 3612. Therefore, as the reservoir 30 rotates relative to the avil 12, the rings 36a and 36c rotate relative to the ring 36!). The seal is lubricated by the capillary action of fluid in the can reaching the seal as and between rings 36a, b and c.

It will now be understood that under no load conditions the anvil 12 will rotate at approximately the same speed as the motor and the impact mechanism will not function thus maintaining the

seals

36a, 36b and 36c static because there is no relative rotation between the can 30 and the anvil 12. This is a real advantage because the seals 36a, 3fib and 36c can not be heated up under free speed no load conditions. Under load conditions the impact mechanism will impact thus effecting the

seals

36a, 36b and 36c. However under load conditions the speed of the seals 36a, 36b ad 36c is greatly reduced because the seal speed is approximately the B.P.M. of the impact wrench which is much less than the impact speed.

It can thus be seen that the dynamic seal life is pre- 61 served through the reduction and lack of relative motion between the anvil 12 and the can 30 at critical high speed operation and the further reduction of relative motion between anvil 12 and the can 30 at impact conditions. It will also be see that the anvil side 40 of the dynamic seal 36 will be dry and that the can side 42 will be coated with the lubricant in the can 30. This further serves to prolong the life of the dynamic seal 36, because the can side 42 of the dynamic seal 36, which is the friction side,

ill be subjected to the friction of rotation and since the can side 42 will be adequately lubricated the dynamic seal 36 will have a longer life.

The static seal 38 can be any type of well known seal, such as an O-ring, and is disposed in a recess 44 in the cam 28, and serves to prevent lubricating fluid from escaping from the can 30, to the motor area of the impact wrench 10.

It will be recognized by those skilled in the art that the objects of the present invention have been achieved by providing an impact mechanism that will greatly reduce seal failure and also an impact mechanism that contains only two seals.

While in accordance with the patent statutes a preferred embodiment of the present invention has been illustrated and described in detail, it is to be particularly understood that the invention is not limited thereto or thereby.

I claim:

1. An impact mechanism comprising:

a reservoir containing lubricating fluid;

a hammer mounted within said reservoir;

means for rotating said hammer and reservoir;

an anvil extending into said reservoir and surrounded by said hammer for continuous rotation with said hammer and reservoir when a load below a predetermined minimum is applied to said anvil and for intermittent rotation with said hammer and reservoir when a load above said minimum is applied to said anvil whereby said lubricating fluid lubricates the contacting surfaces between said anvil and said hammer; and

first seal means between said reservoir and said anvil for.preventing loss of lubricating fluid from said reservoir.

2. The impact mechanism of claim 1 wherein said first seal means includes a plurality of friction rings in contact with each other and encircling said anvil, at least one of said friction rings having an O-ring engaging said reservoir and at least one of said friction rings having a O-ring engaging said anvil.

3. The impact mechanism of claim 2 wherein said first seal includes means for biasing said friction rings together.

4. The impact mechanism of claim 3 further including second seal means between said hammer and said rotating means.

5. The apparatus of claim 4 further including a casing surrounding said drive means, reservoir, hammer and anvil.

References Cited by the Examiner UNITED STATES PATENTS 2,501,542 3/1950 Sheldon 173 123 X 3,070,378 12/1962 Bojako et a1. 277- s3 X 3,123,365 3/1964 Gorman 277 s3 3,169,775 2/1965 Macaluso 277-433 X 3,210,963 10/1965 Burnett 173 93 X LAVERNE D. GEIGER, Primary Examiner. E. J. EARLS, Assistant Examiner.

Claims

1. AN IMPACT MECHANISM COMPRISING: A RESERVOIR CONTAINING LUBRICATING FLUID; A HAMMER MOUNTED WITHIN SAID RESERVOIR; MEANS FOR ROTATING SAID HAMMER AND RESERVOIR; AN ANVIL EXTENDING INTO SAID RESERVOIR AND SURROUNDED BY SAID HAMMER FOR CONTINUOUS ROTATION WITH SAID HAMMER AND RESERVOIR WHEN A LOAD BELOW A PREDETERMINED MINIMUM IS APPLIED TO SAID ANVIL AND FOR INTERMITTENT ROTATION WITH SAID HAMMER AND RESERVOIR WHEN A LOAD ABOVE SAID MINIMUM IS APPLIED TO SAID ANVIL WHEREBY SAID LUBRICATING FLUID LUBRICATES THE CONTACTING SURFACES BETWEEN SAID ANVIL AND SAID HAMMER; AND FIRST SEAL MEANS BETWEEN SAID RESERVOIR AND SAID ANVIL FOR PREVENTING LOSS OF LUBRICATING FLUID FROM SAID RESERVOIR.