US2664628A - Pole pruner head - Google Patents

Description

Jan. 5, 1954 T. M. PORTER 2,664,628

POLE PRUNER HEAD Filed Nov. 1e, 1951 Patented Jan. 5, 1954 POLE PRUN ER HEAD Thomas M. Porter, Brookline, Mass., assigner to H. K. Porter, Inc., Somerville, Mass., a corporation of Massachusetts Application November 16, 1951, Serial No. 256,736

2 Claims. (Cl. 30-.249)

This invention relates to pole pruners of the type -having a hook member, in the general form of an inver-ted J, across the throat of which sweeps a cutting blade, and the object is to provide improvements relating `to the control of the blade whereby an eflicient structure not likely to be fouled by twig-s or the like is provided and one which may be economically produced.

My invention will be well understood by reference to the following 4description of the illustrative embodiment thereof shown by way of example in the accompanying drawings, wherein:

Fig. 1 is a fragmentary side elevation of a pole pruner illustrative of the invention;

Fig. 2 is a similar View showing the jaws closed; and

Fig. 3 is Aa section on line 3-3 of Fig. l.

The pruner illustrated in the drawings comprises a J-shaped member which, `as shown, is formed from two spaced identical elements lil-I and lll-1' secured together at their distal ends and at the lower ends of theshank of the J. A cutting blade I2 is mounted on pivot I4 adjacent the yupper end of the stem of the J and has an edge portion to sweep `across the throat of the J to effect a cut in cooperation with the workengaging portion. The parts I--l and lll-r may be secured to the pole l5 by means of side plates IB-l and l-n What has been described in this paragraph is not in itself new.

The blade l2 has a rearward extension to provide a lever arm of suitable length to which rope 26 may be attached to operate the primer. Herein this extension is forme-d by a straight, barlike piece 22 riveted to the side of the blade. Economy in the use of the high-grade steel from which, for efliciency, the blade must be formed, is thus effected and another function is provided for as will hereinafter appear.

The blade is closed to the position of Fig. 2 by pulling on the rope 2li, and some spring means is required to return the parts to the opening position. Springs as hitherto arranged on tools of -this type cause trouble. In general they provide another obstruction at the -head of the pruner, difficult to manipulate in tight places between the branches. Twigs are likely to get between the springs and other .parts of the pruner head and interfere with its operation. The spring itself may be caught and found difficult to free, and may even be damaged.

I ameliorate these conditions by utilizing a cylindrically coiled spring 24 of the extension type, which is positioned so that its `coils closely encircle the lever arm 22 which arm extends through the spring substantially coaxially therewith. The ends of the spring are anchored respectively at 26 to the outer end of the lever arm and at 28 -to the J -shaped member at a point suitably olTset from the pivot lll. The latter anchorage is effected by a relatively long straight extension 30 of the wire of the spring which eX- tension may lie close along the side of arm 22 and the back of the blade l2.

It will be apparent that the spring adds very little bulk to the necessary bulk of the blade lever itself and presents no parts widely spaced therefrom into which twigs or the like may enter. At the saine time the spring is guarded and supported against damage by the member 22 over which it is telescoped.

rJhe inner or lower end of the arm 22 projecting from the sid-e of the blade l2 is in the plane of the J-shaped member Ill--l on that side and it may thus be so arranged that it makes contact with the back of this member'l-l when the parts are closed when the blade has completed its sweep across the throat of the member as illustrated in Fig. 2. The hooked portion of the spring where anchored at 28 bridges the two side pla-tes I8-I and l-r and' forms a stop presented to the side of the blade l2 when the parts .are in the open position of Fig. 1.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, as is in fact clear in several matters from the description itself. Reference is to behad to the appended claims to indicate those principles of the invention exemplified lby the particular embodiment described and which I desire to secure by Letters Patent.

I claim:

1. A cutter head for pole pruners comprising a member of general inverted J form the curve of the J providing a work-engaging portion, a flat blade pivoted adjacent the upper end of the stem of the J and having an edged portion to sweep across the throat of the J to eifect a cut in cooperation with said work-engaging portion, a straight bar-like lever arm rigidly associated with the fblade and extending rearwardly therefrom and means for normally moving the blade to open position comprising a cylindrically coiled extension spring, the coils of which closely encircle the lever arm which -arm extends through the spring substantially coaxially therewith, the ends of the spring being anchored respectively to the outer end of the lever arm and to the upper References Cited in the file of this patent portion of the .l-shaped member at a .point re- UNITED STATES PATENTS mote from the plvot.

2. A cutter head as dened in claim 1 wherein Number Name Date the lever arm is a separate member rigidly se- 11181579 Dodge May 2 1916 cured to one side of the blade and has an inner 117611469 nonkel n June 3 1930 end upstandng from the side of the blade to 212031926 Portel' June 11: 1940 provide a. shoulder which contacts the back of the J --shaped member when the blade has completed its sweep across the throat of the member. 10

THOMAS M. PORTER.

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