US1547528A

US1547528A - Ratchet-and-pawl mechanism

Info

Publication number: US1547528A
Application number: US585805A
Authority: US
Inventors: Willard T Sears
Original assignee: Niles Bement Pond Co
Current assignee: Niles Bement Pond Co
Priority date: 1922-09-01
Filing date: 1922-09-01
Publication date: 1925-07-28
Anticipated expiration: 1942-07-28

Description

July 28, 1925.

W. T. SEARS RATCHET AND PAWL MECHANISM Fil'ed Sept. 1, 1922 HqZ.

Patented July 28, 1925.

UNITED STATES PATENT OFFICE COMPANY, or NEW YORK,

N. Y., A CORPORATION or NEW JERSEY.

RATCHET-AND-PAWL MECHANISM.

Application filed September 1, '1922. Serial No. 585,805.

To all whom may concern Be it known that I, VVrnnann T. SEARS, a citizen of the United States, residing at lrlont-clair, in the county of Essex and State of New Jersey, have invented certain new and useful Improvements in Ratchet-and- Pawl Mechanism, of which the following is a specification.

This invention relates to a ratchet and pawl mechanism and in particular to mechanism of this type for use in connection with a feed mechanism for machine tools.

An object of the present invention is to provide a ratchet and pawl mechanism which will permit variation of the feeding action of a ratchet wheel within fine limits.

Another object of the invention is to vide a particular form of pawl as a part of the feeding mechanism which may be disengaged from its ratchet wheel at any point in its op'e'iativestroke with a minimum of resistance.

One feature which enables me to accomplish 'the above named objects is that the a pawl comprises two members pivotally con nectec together and held, by means of a spring, in relative operative position.

Anotherfeature which is advantageous is that the pawl maybe disengaged from the ratchet wheel by engagement of an intermediate pawl member with an adjustable stop which oscillates this intermediatepawl member and permits the other pawl member to oscillate relative to the first pawl memher and thus disengage itself from the ratchet wheel.

With these and other objects in View, my invention consists in the features of construction and operation set forth in the following specification and illustrated in the accompanying drawing.

In the accompanying drawing annexed hereto and forming a part of this specifica tion, I have shown my invention embodied in a mechanism for slowly rotating a shaft but it will be understood that the invention can be otherwise embodied and that the drawing is not to be construed as defining or limiting the scope of the invention, the

, claims appended to this specification being relied upon for that purpose.

In the drawing:

Figure 1 is a front elevation of the complete mechanism forming the present invention, and

Fig. 2 is a central vertical section of the same.

In the above mentioned drawing, I have shown but one embodiment of the invention which is now deemed preferable, but it is to be understood that changes and modifications may be made within the scope of the appended claims without departing from the spirit of the invention.

Briefly, my invention in its broadest aspect comprises the following principal parts: first, a rotating shaft which may be suitably supported and which it is an object to slowly rotate in a step-by-step manner; second, a ratchet wheel fastened directly to said shaft, third, an oscillating arm; fourth, a reciprocating rod attached to said arm whereby the arm may be oscillated through a constant angular distance with each movement of the rod; fifth, a pawl of novel construction having two pivotally connected members, one of which is adapted to engage the ratchet wheel; sixth, an adjustable stop positioned to engage an extension on the other pawl member.

Rererr ncre detail to the figures of the draw g, a suitable support is provided through which extends a rotatable shaft 11. )n this shaft 11 adjacent the support 10 is a ratchet wheel 12 fixed thereto by means of the lreys 13 as shown. Between the ratchet wheel and support 10 and preferably adapted to oscillate about a bearing l l formed on one of the supporting.

members 10 is an arm 15 which at an intermediate point is attached to a connecting rod 16. By any suitable means, not shown, this connecting rod 16 may be reciprocated so that the oscillating arm 15 may be oscillated through a constant angle with each movement of the rod 16.

On the outer end of this oscillating arm 15 is an intermediate pawl member 17 which is suitably pivoted about a pin 18 in the oscillating arm 15. Near the lower end of this intermediate pawl member 1'? is a small pawl member 19 pivoted to the intermediate member at 20and adapted at its outer end to directly engage the teeth of the ratchet wheel 12. Preferably, and as shown, the two

pawl members

17 and 19 are held in normal Operative positions by means of a spring 21' engaging the

pawl members

17 and 19 and preferably surrounding the pivot 20. A pin 22 in the intermediate pawl member 17 prevents the sive teeth in the ratchet wheel 12 and ad;

vance the ratchet wheel 12 and the rotating shaft 11 through small angles with each reciprocation of the arm 15. As it is frequent- 1y desirablecto vary the rotative movement of the ratchet wheel12 and shaft 11 to effect variable feeds or other iunctions, special means have been PFOVlClEdto restrict the rotative movement ct this ratchet wheel 12 while the oscillating arm 15 may continue to operate through the same distance.

These means comprise an adjustable stop 25 which may be positioned anywhere in the arcuate slot 26 formed in one of the supporting members 10.

'This adjustable stop 25 has a pin 27 outstanding therefrom adapted to be engaged by an integral extension 28 formed on the intermediate pawl member 17..'By positioningthe adjustable stop 25 at any predetermined point in the arcuate slot 26, the

pin 27 may be made to engage and oscillate this intermediate pawl member 17 at any point in the s roke of the oscillating arm 15. As soon as the intermediate pawl member 17 is engaged by this pin 27, the intermediate pawl member 17 is oscillated about its pivot 18 while the other pawl member 19 remains in contact'with a tooth of the ratchet wheel 12. Thus as the pawl 19 remains in contact with the tooth of the ratchet wheel 12, the two

pawl members

17 and 19 are relatively oscillated about the pivot 20 on the intermediate pawl member 17. This oscillating movement'or" the two pawl members is sufficient to move the pivot 20 to. the opposite side of a line extending from' the point of engagement with the pawl member 19 with the teeth of theratchet wheel 12 and the pivot 18 tor theiintermediate member 17 therefore .no further movement of the ratchet wheel 12 will take place but the pawl member'19 will continue to oscillate about the'intermediate member thus eiiectively stopping further advancing movement of the ratchet wheel 12 and shaft 11.

llo'hold the ratchet wheel 12 in its advanced rotative position another pawl member .29 is provided preferably pivotally mounted on the supporting member 10 and engaging another one 01" the teeth of the ratchet wheel 12. It will be seen therefore that a mechanism has been provided which will permit a ratchet wheel 12 to be advanced variable predetermined small dis tances by means of the oscillating arm 15 while the oscillating arm continues to oscillate throughout a'constant angular distance.

What I claim is': 1. A ratchet and pawl mechanism comprising in combination, a'ratchet wheel, an oscillating arm having a pawl thereon adapted to engage and rotate the ratchet wheel, an intermediate pawl member on the arm, an extension on the intermediate pawl member, and adjustable means engaging said extension and causing said intermediate pawl to be oscillated and oscillating the pawl out of driving engagement with the ratchet wheel at any predetermined point in the stroke of the oscillating arm. 7 7

2. A ratchet and pawl mechanism comprising in combination, a ratchet wheel, an oscillating arm having a pawl thereon adapted to engage and rotate the ratchet wheel, said pawl comprising two pivotally connected members having spring means to hold them in operative relative position, an extension on oneof said members, and adjustable means engaging said extension adapted to oscillate the othermember out of driving engagement with the ratchet wheel at any predetermined point in the stroke of the oscillating arm. 7 l

'3. A. ratchet and pawl mechanism comprising in combination, a ratchet wheel, an oscillating arm having a pawl thereon adapted to engage and rotate the ratchet wheel, said pawl comprising two pivotally connected members having spring means to hold them in operative relative position, an extension on one of said members, adjustable means engaging said extension adapted to oscillate the other member out of driving engagement with the ratchet wheel at any predetermined point in the stroke of the oscillating arm, and means to clamp the adjustable means in any desired position.

4-. A ratchet and pawl mechanism comprising in combination, a ratchet wheel, an oscillating arm having a pawl thereon adapted to engage and rotate the ratchet wheel, said pawlcomprising' two pivotally connected members having spring means to hold them in operative relative position, an extension on one of said members, and an adjustable stop adapted to engage said extension whereby the twopawl members are relatively oscillated abouteach other and about the oscillating arm and are disengagedfrom drivingrelation with the ratchet wheel.

In testimony whereof, I hereto signature. 7

WILLARD T, SEARS;