US2500462A - Lever and gear-sector operated locking parallel-jaw wrench - Google Patents

Description

March 14, 1950 A. LAZZARINI LEVER AND GEAR SECTOR OPERATED LOCKING PARALLEL-JAW WRENCH Flled July 5 1947 [2122 enfor 2' am f Patented Mar. 14, 1950 LEVER AND GEAR-SECTOR OPERATED LOCKING PARALLEL-J AW WRENCH Aldo Lazzarini, Van Nuys, Calif.

Application July 5, 1947, Serial No. 759,118

3 Claims. (Cl. 8186) My invention relates to improvements in wrenches of the type having the jaws always parallel to one another regardless of the aperture to which it is held.

It also relates to improvements in that category of wrenches, sometimes called multiple lever wrenches or hand-Vises, the latter designation being due to their self-locking characteristic.

As such it differs from another parallel wrench which I invented and has made the subject of an earlier patent application #756,928.

The object of this invention is to produce a tool having a powerful grip due to its high leverage but being adaptable at the same time to a comparatively broad range of work. Ordinarily, the higher is the leverage, the smaller is the range of work, due to the small maximum aperture of the jaws. In this invention the jaws are pre-set so as to operate from initial varied apertures, such pro-setting being attained almost instantaneously and with very little efiort. In fact, preparatory adjustments by means of thumb screws and the like, involving the guessing of the entity of the final gripping aperture, are with this invention eliminated.

I attain these objects with a device whose design is illustrated in the accompanying drawings and whose operation I now undertake to describe.

Fig. 1 is a view of this device as one would see by removing one side wall of that portion which constitutes the housing. In this figure the working position represented is the open one.

Fig. 2 is a similar view as the above, but showing the wrench in the closed position.

Fig. 3 is a sectional view of the upper part of the wrench, or body (for space convenience the handle portion is broken away), along line 3-3 of Fig. 1.

Similar numerals refer to the same parts as illustrated in all figures.

A main part, designated with small numeral I, constitutes a housing enclosing the other parts of the tool's body. It is formed by two flat walls held parallel by return portions 2 and 3. A tapering elongation 4, extending downward, forms one of the pair of handles of the wrench. Also one of the jaws, 5, is integrally a part of the same housing, straddling the two flat walls of the same at the top.

An oblong perforation in both walls of the housing is indicated by dotted line at 6. This perforation follows an oblique direction for a purpose which will be later explained.

A lever, 1, provides the second handle of the usual pair. The upper portion of the same leverhandle forms a fold providing a cavity, 8. The sides of said fold extend and form two yokes where, inserted in suitable perforations, are' wrist-pins 9 and II]. An arm, II, which preferably will have a small resiliency and is therefore made of spring-steel, connects said lever-handle to the bodys fixed handle extension by means of wrist pin II! at one end, and fulcrum pin l2 at the other, thus making a toggle assemblage.

A head-piece, I3, has an extending lobe with a perforation, which is held in articulate connection with the upper yoke of handle-lever I by wrist-pin 9. The articulated movement of this joint, however, is restrained by an abutting stop formed by said yoke, wherein the head-piece may not swing farther than shown in Fig. 1. It is in the above position that the head-piece I3 is normally kept when idle. A coil spring of the angular thrust type, I4, held by pin l5 within the cavity of the lever-handle, will perform this co-centered with the gear sector, a fulcrum-pin I1 is forced in, being locked therein by friction, and symmetrically protruding its ends into oblong perforations 6 of the side walls, as shown in Fig. 3. It will be noted that theoutline of the perforations 6 of the side walls permit the fulcrum-pin a shifting play of limited extent and respectively illustrated in Fig. 1 (down) and Fig. 2 (up). Obviously the perforations of the two walls will be perfectly aligned.

A toothed bar or rack I8, which has a section profile similar to a T turned upside-down (see Fig. 3) is slidably fitted to suitable guiding tracks 29, formed at the upper edge of the walls of housing I, and projecting inwardly.

The teeth of such rack are intermeshable with the gear sector I6.

Both the gear sector I6 and rack I8 are as broad and strong as possible, their teeth extending in width from wall to wall of the housing.

The other jaw of the required pair, [9, is an integral part of rack I8, the latter being its sliding base.

Located between the flat walls of the housing I is a partition which will provide a small compartment for a spring-and-ball latch 2|, while a small pin, 22, will retain the spring of same at the bottom and provide convenient access for assembling.

the parts.

The ball of said latch is pressed by the spring over and in between the teeth of rack I8, causing may be held despite the action of coil spring 23- due to the ability of this tool to lock itself in such closed position, as will presently be explained.

In visualizing the movement of the combination of levers represented by the parts designated 1 as H, I and it, it will be observed that they go from the respective positions shown in Fig. 1 to those of Fig. 2 in a toggle action manner, causin the small pin 24 to rise counteracting the Spring 23. Wrist-pin Ill describes an arc and by the time it has reached the position indicated in Fig; 2 it has crossed an imaginary straight line between Wrist-pin 9 and pin l2, This puts it beyond a dead point, where any pressure exerted downward in the approximate direction of said straight line upon pin 9, cannot accomplish the result of lowering its position until the leverhandle 1 is purposely swung apart to an extent sufiicient for wrist-pin 1-8 to retrace its arc to the right past the dead point. Until that has occurred, all levers must remain immobilized, that is, locked.

In putting this tool to use, the first step is to spread the handles apart if they dont happen already to be.

knuckle, which will immediately activate spring 23 in overcoming the dead point of the levers.

The action of spring 23, not only will cause the I handle toswing apart, but, on account of the play of pin l'i' within the oblong perforations 5 of the housing walls, the head-piece I3 will descend. at the same time as far down as said oblong perforationswill permit. At that time the teeth of gear 1 sector I 6 will have become disengaged from those of rack it. In such situation the rack l 8 is'readily caused to shuttle one way or the other by handpressing the jaws together or, reversely, by press-,

1 ing the jutting end of the rack l8 into the housone-half tooth spacing in excess of the final gripping aperture. then. close them upon the object to be gripped, a

By wide-opening the jaws and very easy and speedy adjustment is accomplished.

Now, drawing the handles together, the levers will. operate as already explained. The headpiece l3. being kept in; the extended position by spring M Will rise until its gear sector I B is in engagement with rack l8. This movement is guided by the oblique perforations- 6. When the pin H has reached the play limit permitted by said perforations, the head-piece will begin to' pivot therein while the articulate joint of Wrist-pin 9" will become operative despite the pressure of spring M to the contrary.

By a single hand operation, this i i is done with a slight jerk of the small fingers As the head-piece rotates, the rack I8 is impelled to slide and force the jaws to close.

This is the positive gripping action.

As it involves a small displacement of the jaws, and as the ratio of leverage is very high especially when the levers are approaching the dead point, the gripping power is correspondingly great.

During the gripping action of the jaws, the thrust of the gear sector I6 upon the resisting rack l8 would tend to cause the meshed teeth to slide off engagement. To prevent that, the counter thrust developed by fulcrum-pin ii, which isin the opposite direction, is taken advantage of.

That is the purpose of the obliquity of the wall perforations 6. The counter-thrust of the fulcrum-pin i1 upon the upward inclines of said perforations Will tend to keep the teeth meshed as they are. the more gripping resistance. the better. To release the holding grip, the lever-handle I must be swung apart from handle 4 past the dead point of the levers (as already explained), but on account of the counter-action of the powerful grip which has locked the levers very tightly, a small efiort may be required to open the handles. Once the levers surmount the dead point in the opening direction, spring it will cause all moving parts to return all the way tothe open position.

A new feature in the operation of this invention may be attained by a slight modification in the shape of spring l4. Such modification consists in curving the upper end of said spring in a manner as to partly envelop the gear sector head when the latter is flexed upon the lever handle as shown in Fig. 2. Such curvature of the spring and will serve to hold said gear sector head in this position even while it descends during its disconnecting phase. However, it will suddenly extend from the flexed position upon reaching the lower limit of its displacement. The resultant eiiect will be to avert any retracing step of the toothed rack l8, hence the jaws may be made to furtherly close, step by step, at each successive stroke of the handles.

Having thus described my invention. I claim:

1. A parallel self-locking Wrench composed of a housing body having two main walls and a projecting stationary jaw and a fixed handle extending oppositely said jaw; a movable jaw opposing said stationary jaw and having a base forming atoothed rack which is adapted to slide transversely Within the housing body; lever handle; connecting means resiliently linking said lever handle and said fixed handle to form a toggle; a gear sector pivotable within the housing body upon a fulcrum provided by trunnions emerging from the opposite faces of the gear sector and projecting into a pair of co-aligned oblong perforations of the twomain walls of the housing body, such gear sector also having a radial protuberance which is connected articulate joint to the work-end, of saidleve-r handle.

2. A parallel self-locking wrench composed of a housing body having two main walls and a projecting stationary jaw. and'a fixed handle extending oppositely said jaw; a. movable jaw opposing said stationary jaw andhaving a base forming a toothedrack which is adapted to slide transversely within, the housing body; a lever handle; connecting means resiliently linking said lever handle and said fixed handle to form a toggle; a gear sector pivotable within the housing body upon a fulcrum provided by trunnions emerging from the opposite faces of the gear sector and projecting into a pair o! coaligned oblong perforations of the two main walls of the housing body, such gear sector also having a radial protuberance which is connected by articulate joint to the work-end of said lever handle; a spring for biasing said gear sector toward the toothed rack, and a second spring normally acting to swing said lever handle away from the fixed handle.

3. A parallel self-locking wrench composed of a housing body having two main walls and a projecting stationary jaw and a fixed handle extending oppositely said jaw; a movable jaw opposing said stationary jaw and having a base forming a toothed rack which is adapted to slide transversely within the housing body; a lever handle; a bow spring rod resiliently linking said lever handle and said fixed handle to form a toggle; resilient stop means for restraining the sliding motion of said toothed rack; a gear sector pivotable within the housing body upon a provided by trunnions emerging from the opposite faces of the gear sector and projectin to a pair of co-aligned oblong perforations W0 main walls of the housing body, such a second spring normally acting to swing said lever handle away from the fixed handle.

ALDO LAZZARINI.

REFERENCES CITED The; following references are of record in the file o'i this patent:

UNITED STATES PAEIENTS Nuniber Name Date 5 5,357 McIntire June 25, 1907 2,181,621 Johnson Nov. 28, 1938 2,361,607 Daniels Oct. 31, 1944

Images