US2787912A

US2787912A - Two-speed ratchet devices

Info

Publication number: US2787912A
Application number: US393914A
Authority: US
Inventors: Smallpeice Cosby Doua Philipps
Original assignee: Individual
Current assignee: Individual
Priority date: 1952-12-05
Filing date: 1953-11-23
Publication date: 1957-04-09
Anticipated expiration: 1974-04-09

Description

3 Sheets-Sheet l Filed Nov. 2s, 1953 Trai FIGB April 9, 1957 c. D. P. sMALLPElcE TWO-SPEED RATCHET DEVICES 3 Sheets-Sheet 2 Filed Nov. 23, 1953 FIGA.

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April 9 1957 C. D. P. sMALLPElcE 2,787,912

TWO-SPEED RATCHET DEVICES Filed Nov. 25, 1953 3 Sheets-Sheet 3 TWG-SPEED RA'CHET DEVICES Cosby Donald Philipps Smallpeice, Swanwick Shore, near outhampton, England Application November 23, 1953, Serial No. 393,914

Ciaims priority, application Great Britain December 5, 1952 6 Claims. (Cl. 74-142) States Patent A form( of ratchet mechanism having two ratios, and one which does not involve the use of gearing.

Though not in any way limited in this respect, the invention is particularly of use for ratcheting a winch in yacht racing, the high speed being used for initially taking in the sheet rapidly and the low speed for electing the final tautness of the sheet.

According to the invention, a ratchet mechanism has an operating lever which passes across the axis of the ratchet (when the lever is moved from one extreme angular position to the other) or of an equivalent part and of which the fulcrum is off-set from though parallel to the axis of the ratchet so that a projection on the lever on one side of the axis will enable an angular movement to be given to the ratchet which is less than that of the lever, whereas a projection on the other side of the axis will enable an angular movement to be given to the ratchet which is greater than that of the lever, thereby providing two ratios between the lever and ratchet.

The ratchet mechanism, of course, has means for selectively moving the projections into the operative positions, and, preferably, selection is effected by the movement of the operating lever in a direction radial to its fulcrum.

In the accompanying diagrammatic drawings:

Figure l is a schematic sectional elevation of a winch having applied to it a simple form of ratchet mechanism according7 to the invention, the section being taken on the line -l of Figure 2;

Figures 2 and 3 are sectional plans on the broken line 2 2 of Figure l showing the high speed projection in operative engagement in Figure 2, and the low speed projection in operative engagement in Figure 3;

Figure 4 is a schematic sectional elevation of a winch fitted with a preferred form of ratchet mechanism according to the invention; and

Figures 5 to 8 are all sectional plan views taken approximately on the broken line 5 5 of Figure 4.

Referring first to the construction of Figures 1 to 3, the winch 1t is tast with a stub shaft 12 which is formed integrally with or otherwise secured to a ratchet 13, shown as being in the forrn of a toothed ratchet wheel. The winch is journalled, for example, as indicated at l5, on a cover plate i7 for the ratchet, the cover plate coacting with a stationary base 18 which has on one side a slot 19 to receive the operating lever 20 and limit the angular movement thereof.

In Figures 1 to 3 the operating lever 20 i's shown as being slidingly fulcrumed on a pin 22 carried by the base 18 and working in a radial slot 23 of the arm. Spaced apar-t from one another along the length of the arm, and on opposite sides of the ratchet (with the axis of which the fulcrum pin 22 is parallel though eccentrically arranged), are two

projections

26, 27 adapted to coact with the teeth 28 of the ratchet dependently upon the axial position of the operating lever. Obviously, in practice, these projections might taire the form of spring-pressed pawls. 29 is a non-return spring-pressed pawl carried by the cover plate 17.

With the parts in the positions shown by Figure 2,

the angular movement given to the ratchet when thei operating lever is moved from one extreme angularposition to the other (it is shown in Figure 2 and in Figure 3 as passing diametrically across the ratchet--i. e., in an intermediate position) will be greater than that of the lever. In the position of Figure 3, however, the angular movement to be given to the ratchet will be less than that given to the lever.

In the construction of Figures 4 to 8, the winch 31 is journalled on a stub shaft 32 which, in this case, is formedl integrally with a cover plate 33 secured to a stationary base 34 by screws 35. The lower end of the winch is ifast with a ring 37 with which coact a set of rollers 384 of a free-wheel or overrunning clutch having a ratchet 39 in the form of a central cam disc which is journalled on a spigot 4%. Fast with the spigot 40 is another-cam ring 42 coacting with the ring 37 through another set of free-wheel rollers 43. rille ratchet 39 has a hole 44a to receive a driving pin 44 fast with a rotatable member in the form of a plate 45' which is shown as being angu. larly movable about the axis of the winch, the pin 44 being able to work in an arcuate slot 46 provided in the cover plate 33.

Only the operative end o the operating lever 48 is shown in Figures 4 to 8, and it will be understood that the lever may be continued as far as desired for manipulation by an operator. The operative end of the lever is slidably carried in a diametrical slot of a trunnion 50 which in turn is angularly movable in a recess 51 of the stationary base provided for the purpose, the axis of the trunnion being parallel to, i. e., oit-set from, the axis of the winch. The plate 45 has two recesses provided in its periphery which, when the operating lever is in the positions of Figures 5 and 7, can selectively receive the adjacent projections or

pins

53, 54 which are fast with the lever and mounted on a centre line thereof.

Thus, with the high speed pin 54 engaged with the plate 45, as shown by Figure 7, the plate can be turned to the position shown in Figure 8 for a given angular movement of the lever as dened by a slot (like the slot 19 of Figures 2 and 3) in the adjacent wall of the base, while the pin 44 moves along the arcuate slot 46, thus rapidly to turn the winch through the ratchet 39-i. e.,

v through the roller free-wheel including the rollers 38.

On the return stroke of the operating lever the free-wheel including the rollers 43 prevents rotational movement of the winch.

When, however, the load becomes excessive, the operating lever is slid inwardly (Figure 5) to bring the slow speed pin 53 into driving engagement with the plate 45, and the operating lever can then be moved into the position shown by Figure 6. A comparison of Figures 6 and 8 as regards the movement of the pin 44 along the arcuate slot 46 indicates the gear ratio involved, i. e., the ratio of the distances of the

pins

53, 54 from the pivotal axis of the tiunnion 50 when the pins are in the operative position.

The extension 56 on the plate 45 is for keeping the associated pin 54 from running over the end of the plate.

It will be understood that the ratchet 39 of the roller free-Wheel could, if preferred, be a toothed ratchet wheel coacting with a pawl. In like manner, the holding roller i A Fatented Apr. 9, 1957-"-4 3 free-wheel (37, 42 and 43) could be replaced by a pawl coacting with a toothed ratchet wheel.

In the particular example the ratchet 39 and the rotatable member 45 are coaxial with one another, but they need not be. In the latter case the operating lever might not pass across the axis of the ratchet when moved between its extreme positions, but it would, of course, pass across the axis of the rotatable member 45. The advantage of having a rotatable member which is not concentric with the ratchet is that it provides a means of altering the ratio between the lever and ratchet.

What I claim as my invention and desire to secure by Letters Patent of the United States is:

1. A two-speed ratcheting mechanism including a oneway driving device having a driving element, an operating lever movable about its fulcrum, means limiting the movement of the lever between two extreme angular positions, said fulcrum being olf-set from but parallel to the axis of said driving element and arranged so that during movement of the lever between its extreme angular positions the lever will pass across the axis of the driving element, and projections on the lever which are selectively movable into operative positions to drive said driving element at different speed ratios by sliding movement of the lever along its longitudinal axis.

2. A ratcheting mechanism, according to claim l, in which the projections are fast with said lever to be carried into their operative positions dependently upon the direction of the longitudinal movement of the lever.

3. A ratcheting mechanism comprising a one-Way driving device having a rotatable driving element, an operating lever, a fulcrum for the lever having an axis which is off-set from but parallel to that of the driving element, means connecting the lever for sliding motion along its longitudinal axis and relatively to its fulcrum, a plate mounted for rotation about the axis of the driving element andinterposed between the latter and the lever, a pin fast with said plate and engaged with a hole in the driving element, and longitudinally spaced projections on said lever adapted to selectively engage oppositely disposed recesses of said plate in the respective longitudinal positions of the lever to enable the driving clement to be turned at different speed ratios.

4. A ratcheting mechanism, according to claim 3, in which a cover is interposed between said plate and the driving clement, the cover coacting with a stationary base to enclose the fulcrurn of the lever and said rotatable plate, said stationary base having in it a slot which is arcuate about the axis of the driving element to receive said pin.

S. A ratcheting mechanism, according to claim 3, and in which the one-way driving device is of the roller freewheel type, having an outer ring engaged by rollers coacting with the driving element, in combination with a one-way brake device of the roller type and sharing the same outer ring.

6. A ratcheting mechanism, according to claim 3, in which the fulcrum for the operating lever includes a disc rotatable about a fixed axis, the lever being slidable in a diametrical slot of the disc during sliding motion of the lever along its longitudinal axis.

References Cited in the tile of this patent UNITED STATES PATENTS 1,135,655 Beemer Apr. 13, i915 1,985,406 Galkin DCC. 25, 1934 FOREIGN PATENTS 458,676 Germany Apr. 17, 1928