US2714250A - Hydraulic pruning and cutting tool - Google Patents

Description

A. B. TWEDT HYDRAULIC PRUNING AND CUTTING TOOL Filed Sept. 14, 1954 Aug. 2, 1955 mum: 1

United States Patent HYDRAULIC PRUNING AND CUTTING TOOL Arthur B. Twedt, Portland, Oreg. Application September 14, 1954, Serial No. 456,015

3 Claims. (Cl. 30-180) This invention relates to'improvements in pruning and cutting tools and has for one of its principal objects the provision of a tool of this character which is actuated by fluid pressure generated by a self-contained manually-actuated pump. 1

A further object of the invention is the provision of a tool which is of simple, efiicient, durable, light-weight construction of any desired length and which may be conveniently engaged with a limb of a tree for severing the same with a minimum of effort on the part of the op rator.

The foregoing and other objects will appear as my i nvention is more fully hereinafter described in the following specification, illustrated in the accompanying drawing-and finally pointed out in the appended claims.

In the drawing:

Fig. 1 is a side view of a pruning and cuttingitool made in accordance with my invention partly in section and with fragments broken away for convenience of illustration.

Figs. 2 and 3 are fragmentary front views of the top and bottom ends respectively of Fig. 1.

Fig. 4 is a sectional top plan view taken along the .line 4-4 of Fig. l.

Fig. 5 is a rear view of Fig. 1.

Fig. 6 is a detail view of a modified form of cutter head and anvil.

Fig. 7 is a top plan view of the anvil shown in Fig. 6.

Referring now more particularly to the drawing:

The main body of the invention, as indicated generally by reference numeral 1, is in the form of an elongated hollow tube which may be of any desired length. The tube is closed at its top end by a cylinder 2 and at its bottom end by an insert 3 secured within the tube by means of bolts 4. The bolts also secure to the bottom end of the tube, a channel element 5 whose side walls are turned inwardly toward each other at their bottom ends as at 6 to form a limit stop for the downward swing of an actuating lever 7 which is pivotally attached as at 8 to the side walls of the channel and pivotally connected as at 9 to the bottom end of a piston 10 which is slidably mounted within a vertical bore 11 formed in the insert 3. The lower end of the piston extends through any approved type of packing gland or ring-seal 12 held in place by a collar 13 threaded into the bottom end of the insert and locked into position by one of the bolts 4. The lever 7 is in the form of a clevis within whose closed end is permanently secured by any suitable means, a pin 14 which extends upwardly from the top end of the lever for attachment to an actuating handle 15.

From the foregoing, it will be seen that as the handle 15 is moved downwardly and upwardly into the broken and full line positions shown in Fig. 1, the lever 7 will impart vertical reciprocal motion to the piston 10 within the bore 11. Disposed within the tubular main body 1 is a fluid reservoir in the form of an inverted rubber cylinder 16 whose bottom end is secured as at 17 to the top end of the insert 3 in any approved manner. The cylinder 16 is filled with fluid which will be drawn through a duct 18,,around the reduced diameter end of a needle valve 19,

past a spring-pressed check valve 20, and into the bore.

11 through a passageway 21 upon the downward, or suct-ion stroke, of the piston 10. The duct 18 is ported as at 22 into a duct 23 whose bottom end is provided with a spring-pressed check valve 24. This bottom end of the duct 23 is in communication through a duct 25 with the interior of the bore 11. The top end of the duct 23 is provided with a fitting 26 disposed on the interior of the reservoir 16 and connected to the bottom end of a tube 27 which extends upward through the top of the reservoir and is sealed with respect thereto. The top end of the tube is in open communication, by means of a fitting 28, with the interior of the cylinder 2 within which is operatively disposed a piston 29 whose top end is connected as at 30 to an anvil 31 and whose bottom end is provided with a cup piston 32.

The top end of the tubular main body 1 is slotted downwardly as at 33 to receive a pair of plates 34 whose inner edges are welded to the outside wall of the cylinder 2. The plates 34 are arranged on opposite sides of the lower end of a fixed cutter head 35 and are secured thereto by bolts 36 passing through the outwardly turned ends 37 of a pair of clamping bands 38 which, when the bolts are tightened, will securely grip the top end of the tubular member 1 to further stabilize the mounting of the cutter head.

A pair of tension springs 39 are secured at their top ends in any approved manner as at 40 to the sides of the anvil 31 and at their bottom ends as at 41 to a band 42 disposed beneath the bottom clamping band 38 and held against it by the tension of the springs.

The inside edge of the anvil 31 is slotted inwardly as at 43 to slidably embrace the vertical inner edge of the cutter head .35. The top end of the cutter head is extended across the anvil as shown and the bottom edge of the extended portion is ground to a knife edge as at 44.

The operationof the deviceis as follows:

When for example, a branch of a tree, as indicated at 45 in broken lines in Fig. 2, is to be cut by the device, the cutting edge 44 of the cutter head is hooked over the branch and the device is thereby suspended. Following this needle valve 19 is screwed down to close port 22 after which handle 15 is pivoted away from the body of the tool, thus drawing oil past needle 19 and check valve 20 into bore 11, and then upon intermittent upward movement of the handle 15, and thereby upward thrust of the piston 10, after the bore 11 has been filled with fluid from the reservoir 16 as aforesaid, fluid will be forced through the duct 25 into the duct 23 upon opening the check valve 24, then through the tube 27 and into the cylinder 2 beneath the piston and piston cup disposed therein. The intermittent fluid pressure within the cylinder 2, caused by the intermittent actuation of the handle 15 and piston 10 as aforesaid, will force the piston 29 and anvil 31 upwardly against the branch to force it against the cutting edge 44 to be severed thereby.

Upon completion of the cutting operation and to restore the anvil to its position shown in Fig. 1, it is merely necessary to retract the needle valve 19 from its seat in the port 22 to enable the fluid, now under pressure from the spring-loaded piston 29, to return from the cylinder 2 to the tube 27, duct 23, port 22, thence upwardly to the duct 18 and back to the interior of the reservoir 16, whereupon needle valve 19 is again screwed down to close port 22 in preparation of the next cutting action.

The reservoir enables the device to be used effectively in any position including an inverted position without any fluid leaks.

The modified form of cutter head and anvil illustrated in Fig. 6, can be readily applied to the top end of the mechanism shown in Fig. 1 and operated by the piston 29A therein. The cutting edge 44A of the cutter head is of arcuate shape as shown for cooperation with an anvil 46 bifurcated as at 46A and pivotally attached as at 47 to the cutter head and formed with a convex top surface 48 and a bottom surface 49 formed on a radius to which the top end of the piston is tangential at all times throughout vertical swinging movement of the anvil about its pivot point 47. The outer end portion of the anvil is slotted as at 51 to embrace the cutting edge 44A as it approaches the top of its upward stroke, and alongside the slot is an insert blade 52 for cooperation with the cutting edge of the cutter head.

To opposite sides of the anvil I attach the top ends of a pair of compression springs 53 whose bottom ends are attached as at 54 to a band 55.

In the event it becomes necessary or desirable to actuate the device by fluid pressure from an outside source, I provide a plug 55 in a threaded opening 56 communicating with the interior of the duct 23. When the plug is removed, a terminal fitting (not shown) on a pressure supply line may be secured within said opening. With the needle valve 19 closed the pressure will go directly through the tube 27 into the cylinder 2.

While I have shown and described particular forms of embodiment of my invention, I am aware that many minor changes therein will readily suggest themselves to others skilled in the art without departing from the spirit and scope of the invention.

Having thus described my invention, what I claim as.

new and desire to protect by Letters Patent is:

l. A pruning and cutting tool comprising in combination an elongated tubular main body member closed at its top end by a cylinder having a piston operatively disposed therein and closed at its bottom end by an insert, said insert being bored along its length, said bore being in communication with a fluid reservoir disposed on the interior of the hollow tubular main body member, a piston operatively disposed in said bore, lever means for actuating said piston in the bore, said bore being in communication through valve means with said piston in said cylinder, a

cutter head secured to the top end of said hollow tubular main body member and having a cutting edge spaced apart therefrom, an anvil carried by said piston in said cylinder and adapted to be moved by said last-mentioned piston toward said cutting edge to sever an object placed upon and carried by the anvil.

2. A pruning and cutting tool comprising in combination an elongated tubular main body member closed at its top end by a cylinder having a piston operatively disposed therein and closed at its bottom end by an insert, a fluid reservoir made of expansible material disposed on the interior of the tubular main body member and secured at its bottom end to said insert, said insert being bored along its length, said bore being in communication with the interior of said reservoir, a piston operatively disposed in said bore, lever means swingably attached to the bottom end of said tubular main body member and connected to said piston in the bore for actuating the same, a tube disposed on the interior of said reservoir and connected at its bottom end through valve means with said bore in the insert, said tube being in open communication at its top end with the interior of said cylinder, a cutter head secured to the top end of said hollow tubular main body member and having a cutting edge spaced apart therefrom,

an anvil carried by said piston in said cylinder and adapted to be moved by said last-mentioned piston toward said cutting edge to sever an object placed upon and carried by said anvil, resilient means interconnecting said anvil to said hollow tubular main body member to return said lastmentioned piston to an inoperative position within said cylinder.

3. A pruning and cutting tool as in claim 2, wherein said anvil is pivotally attached to said cutter head and bears against the top end of said last-mentioned piston at all times under the influence of said resilient means.

Wilson Aug. 5, 1902 Rudolph Sept. 30, 1941

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