US2030585A - Pruning shears - Google Patents

Description

Feb. 11, 1936.

c. G. HAMPTON 2,030,585

PRUN I NG SHEARS Filed June 14, 1933 INVENTOR C G. Hanzp ton Q mm;

ATTORNEY Patented Feb. 11, 1936 UNITED STAES PATET FFIQE 1 Claim.

This invention relates to pruning shears and particularly to the mounting of the jaws in the necessary povotal relation with each other. The principal objects of my invention are to provide a structure for the purpose which will provide for the automatic lubrication of the joint, which will prevent any wobble or transverse separation of the jaws while permitting of the use of thinner hubs than is now feasible, which provides for a take-up for wear so that the jaws can be always maintained in the proper cutting relationship, and to connect the hubs in such a manner that there are no protruding bolt heads or nuts to catch against the parts being trimmed or pruned as is usually the case.

A further object is to arrange the jaws relative to their hubs so that when the jaws are spread apart a relatively thick limb to be cut may project to the base of the jaws at the hubs, thus giving an excellent cutting leverage on the limb when closing the jaws. Also one jaw is preferably provided with teeth acting to prevent the limb or other piece to be cut from any tendency to slip outwardly from between the jaws as the latter are closed.

A further object of the invention is to produce a simple and inexpensive device and yet one which will be exceedingly effective for the purpose for which it is designed.

These objects I accomplish by means of such structure and relative arrangement of parts as will fully appear by a perusal of the following specification and claim.

In the drawing similar characters of reference indicate corresponding parts in the several views:

Figs. 1 and 2 are side views of the jaw end of.

the shears taken on opposite sides and showing the jaws partly opened or spread.

Fig. 3 is an enlarged fragmentary section on the line 3-3 of Fig. 1.

Fig. 4 is a-perspective View of the pivot pin detached.

Fig. 5 is a fragmentary enlarged cross section on the jaws shown in overlapping relationship to each other.

The shears comprise shanks l and 2 to the outer ends of which suitable handles are connected as usual. The shanks are formed with large flat hubs 3 and 4 respectively from which what may be considered as the movable and fixed jaws 5 and 6 project. These jaws are of the usual convex and concave contour respectively and are disposed in opposite relation to the corresponding shanks.

The manner in which the hubs are pivoted to gether is the most important feature of my invention and will now be described. The pivot is in the form of a relatively large cylindrical pin having different sized portions 1 and la with an abrupt shoulder 8 between the same. The smaller portion E projects through the hub t and is secured thereto by heading over the end of the pin so that it is flush with the outer face of the hub as shown in Fig. 3. The shoulder 8 is then pinched firmly against the inner or opposite face of the hub 4, so that the secured portion of the pin cannot turn and the large portion la of the pin projects into and turns in the hub 3, said pin terminating substantially flush with the outer face of the hub 3.

The pin is bored out from the end opposite the portion 1a to form a relatively large chamber 9 for a lubricant such as a piece of saturated felt it, said chamber being normally closed in an oiltight manner by a cover plate '5 l secured on the hub 4 over the adjacent end or" the pin. One or more oil passages l2 are drilled from the chamber to the periphery of the portion la of the pin to conduct lubricant to the adjacent surface of the hub bore.

A plate I3 overhangs the hub 3 and the adjacent end of the pin and also extends over the adjacent portion of the shank 2 of the other hub, from which shank a block I4 projects for engagement with the adjacent portion of said plate. :7

A countersunk cap screw !5 secures the plate to the block and a similar screw it connects the plate and pin axially of the latter. Removable shims ll are placed between the plate and block and between the plate and the hub 3 or the pin la.

These shims provide for adjusting in position of the plate l3 which may be necessary due to any wear between the hubs and jaws so that the latter may be always maintained in the close relationship necessary for emcient cutting.

To prevent the possibility of any tipping of the hub 4 away from the hub 3 a plate l3 may be mounted on the shank l in a manner similar to the plate 13 and in overhanging and close relation to the adjacent portion of the hub 4, as shown in Fig. 2.

The hubs opposite the shanks for a portion of their circumferential extent at least equal to the arc of turning of the jaws from a closed to a fully open position are countersunk with the pin and f the maximum cutting leverage against saidpart as will be evident, the edge of the convex jaw 5 curving inwardly toward its hub so that any slipping of said part engaged. thereby is practically eliminated. 7

To further prevent slipping the cutting edge of the jaw 6 is formed with ratchet shaped teeth I9 facing in the direction of the hub. To prevent possibility of the edge of the jaw 5 catching against the ends of the various teeth as said jaw moves over the teeth successively with the closing of the jaws, the adjacent surface of the jaw 6 at the outer ends of the teeth is beveled slightly as shown at 2% in Fig. 5 so that the jaw 5 will ride smoothly over the teeth. At the same time the sides of the teeth for the major portion of their length are on the normal level of the adjacent surface of the jaw ii so that proper cutting cooperation with the edge of the jaw 5 is assured.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention 7 as set forth herein.

While this specification sets forth in detail the present and preferred construction'of the device, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined by the appended claim.

Having thus described my invention what I claim as new and useful and desire to secure by Letters Patent is:

In a pruning shears having superimposed j awhubs from which the shanks of the shears project, a pivot pin for the hubs, non-removably V mounted in one hub and on which the other hub

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