US3136170A

US3136170A - Automatic tensioner

Info

Publication number: US3136170A
Application number: US247091A
Authority: US
Inventors: James J Murray
Original assignee: Individual
Current assignee: Individual
Priority date: 1962-12-26
Filing date: 1962-12-26
Publication date: 1964-06-09
Anticipated expiration: 1981-06-09

Description

June 9, 1964 J. J. MURRAY AUTOMATIC TENSIONER Filed Dec. 26, 1962 INVENTOR. JAMES J MU RRAY ATTORNEY United States Patent lice 3,136,170 AUTOMATIC TENSIONER James J. Murray, 14011 Oakland Ave, Detroit 3, Mich. Filed Dec. 26, 1962, Ser. No. 247,091 4 Claims. (Cl. 74-242.11)

This invention relates to power transmission and particularly to the transmission of power by chain or belt driven mechanisms.

An object of the invention is to provide a device which will automatically maintain tension on a chain or belt drive.

Another object of the invention is to provide a device of the character indicated which is particularly suitable for use on power drives which have both forward and reverse action.

A further object of the invention is to provide a device of the character indicated, which is constructed and arranged so that it will automatically maintain tension on a fixed-center drive, whether it is operating in a forward or reverse direction.

Another object of the invention is to provide a chain or belt tensioner which consists of a minimum number of parts, is economical to manufacture, and is easy to install on new or old equipment without special tools.

Another object of the invention is to provide a device of the character indicated which is constructed and arranged so that it swings from side to side to automatically accomplish the slack take up, when the drive changes from forward to reverse.

Another object of the invention is to provide a device of the character indicated, which is constructed and arranged so that the necessity of down time for making adjustments is entirely obviated.

Another object of the invention is to provide a device of the character indicated, which is constructed and arranged to automatically take up the slack and to dampen the vibration in a forward and reverse chain driven ma chine.

Another object of the invention is to provide a device of the character indicated, which is constructed with a novel spring biased arm, which is positioned and arranged so that it swings through an arc sufiicient to automatically take up the slack on both the forward and reverse sides of a chain drive, whereby to eliminate any tendency of the slack in the chain to damage the equipment by breaking off sprocket teeth, or jamming the drive by back lash, or by jumping off the sprockets.

The foregoing and other objects and advantages of the invention will become more apparent as the description proceeds, reference being made from time to time to the accompanying drawings forming part of the within disclosure, in which drawings:

FIG. 1 is a plan view, with parts broken away, of a device embodying the invention.

FIG. 2 is a side elevational of the device shown in;

- FIG. 1, with parts broken away.

FIG. 3 is a section taken substantially on the line 3-3 of FIG. 2.

FIG. 4 is a diagrammatic view of the device shown in FIG. 1, combined with a forward and reverse drive mechanism.

Referring now more particularly to the drawings, it will be understood that in the embodiment herein disclosed, the reference character 7 indicates a base, or mounting plate, having apertures 8 for receiving bolts (not shown) by which the device may be secured to a machine, which is motivated, as shown in FIG. 4, by a forward and reverse chain drive.

The device is preferably mounted so that the arm 9 3,136,170 Patented June 9, 1964 may swing approximately 60 to either side of the positiOn shown in FIG. 1, ment may be as much as on either side.

The arm 9 is bored to receive the pivot shaft 10 which is press fitted or otherwise secured in a bore formed in the base 7.. A suitable bearing element 12 is positioned between the arm 9 and the shaft 10, so that the arm may freely pivot on the shaft. An idler which may be a sprocket as shown at 13 or a pulley or the like, which 18 pivoted for rotation on a pivot shaft 14, which passes through another bore 15 formed in the arm 9. The shaft 14 is secured by a nut 16 and is provided with a bearing member 17, so that the idler sprocket 13 may rotate freely thereon.

The arm 9 is spring loaded as follows: A stiff coil spring 18 is mounted around, as shown in FIGS. 2 and 3, the pivot shaft 10 and has

end extensions

19 and 20 which respectively engage the opposite sides of a pair of

pins

21 and 22. The pin 21 is an anchor pin and is secured to the base 7 and the pin 22 is a spring actuating pin and is secured to the arm 9 and extends through an opening in the top cover plate 23. The cover plate 23 is in contact with a dust cover 24, which encircles the spring 18 and the shaft 10. The cover plate 23 has a central opening to receive the pivot shaft 10 and rotates with the arm 9 by means of the pin 22. The assembly is held together by the nut 25 which engages a reduced threaded extension 10A of the shaft 10.

Washers

26 and 27 complete the assembly.

As shown in FIG. 4, the device is mounted so that the idler sprocket 13 contacts the chain 28, which engages the driven sprocket 29 and the drive sprocket 30, which is rotated in forward and reverse directions by a suitable motor (not shown). The solid lines show the chain and tension arm when in forward direction and the broken lines, show their positions and relation when in reverse.

When the arm 9 is moved to the left (FIG. 1) the actuating pin 22 will move the spring extension 19 to the left while the extension 20 is held by the anchor pin 21. This places tension on the spring 18 in one direction. When the arm 9 is moved to the right (FIG. 1) the actuating pin 22 will move the extension 20 to the right while the extension 19 is being held by the anchor pin 21. This places tension on the spring 18 in the opposite direction. When the arm 9 is in the position shown in FIG. 1, the spring 18 is balanced and the arm is at rest. As soon as the idler sprocket 13 at the end of the arm 9 is brought into engagement with the chain 28 (FIG. 4) and the chain 28 is moved, the arm 9 will swing in the direction of the movement of the chain causing tension to be built up in the spring as described above. On the reverse of the chain tension will build up on the other side of the spring. The spring tension so built up, will automatically take the slack out of the chain in forward or reverse motions.

It is believed that the operation of the device is obvious from the foregoing description.

Having described my invention, what I claim and desire to secure by Letters Patent is:

l. A device of the character described, comprising a base plate, a pivot shaft secured to said base, an arm pivotally supported on said shaft, an idler on the free end of said arm, an anchor pin secured to said base plate, a second pin secured to said arm, and movable therewith, a coil spring surrounding said shaft and having its respective ends positioned on opposite sides of said anchor pin and said second pin and arranged so that upon a pivotal movement of said arm and said second pin in either direction on said shaft, tension is built up in said spring.

2. The structure of claim 1 in which said anchor pin on said base and the said pin on said arm when normally at although in extreme cases the move 3 rest are in alignment with the longitudinal axis of said pivotable arm.

3. The structure of claim 1 in which there is a rotatable cover plate spaced from said base plate and a dust cover surrounding said pivot shaft and said spring, and positioned between said base plate and said cover plate.

4. The structure of claim 1, in which there is rotatable cover plate spaced from said base plate and a dust cover surrounding said pivot shaft and said spring, and positioned between said base plate and said cover plate, there being a hole in said cover plate in which is received the said pin secured to said arm, and a second hole in said cover plate for receiving said pivot shaft whereby to permit said cover plate to rotate with said arm about said pivot shaft.

' References Cited in the file of this patent UNITED STATES PATENTS Bernhard Nov. 30, 1954

Claims

1. A DEVICE OF THE CHARACTER DESCRIBED, COMPRISING A BASE PLATE, A PIVOT SHAFT SECURED TO SAID BASE, AN ARM PIVOTALLY SUPPORTED ON SAID SHAFT, AN IDLER ON THE FREE END OF SAID ARM, AN ANCHOR PIN SECURED TO SAID BASE PLATE, A SECOND PIN SECURED TO SAID ARM, AND MOVABLE THEREWITH, A COIL SPRING SURROUNDING SAID SHAFT AND HAVING ITS RESPECTIVE ENDS POSITIONED ON OPPOSITE SIDES OF SAID ANCHOR PIN AND SAID SECOND PIN AND ARRANGED SO THAT UPON A PIVOTAL MOVEMENT OF SAID ARM AND SAID SECOND PIN IN EITHER DIRECTION ON SAID SHAFT, TENSION IS BUILT UP IN SAID SPRING.