US3854204A

US3854204A - Self contained pruning mechanism

Info

Publication number: US3854204A
Application number: US00426066A
Authority: US
Inventors: A Gonzales
Original assignee: Individual
Current assignee: Individual
Priority date: 1973-12-19
Filing date: 1973-12-19
Publication date: 1974-12-17
Anticipated expiration: 1991-12-17

Abstract

A portable pruning device which includes a gasoline motor powered hydraulic pump mounted on a sled which is capable of being dragged behind the operator or carried as a backpack, the air for the pump motor being drawn through a chamber in the sled structure to cool the hydraulic fluid which flows through a conduit in the sled structure on one side of the air chamber. In one embodiment a hydraulically actuated shear blade is operatively connected to the pump through hoses and a rotary coupling and is mounted on a modular mast assembly which includes a pair of hollow coaxial pipes rigidly connected together at their ends by a threaded member which is adjustable to put the inner pipe in compression and the outer pipe in tension, relative to each other, thereby forming a rigid, lightweight structure, the inner pipe of the mast assembly carrying the hydraulic fluid to operate the shearing blade.

Description

United States Patent [191 Gonzales, Jr.

1 SELF CONTAINED PRUNING MECHANISM [76] Inventor: Adrian Gonzales, Jr., 1300 Graham Hill Rd, Santa Cruz, Calif. 95060 [22] Filed: Dec. 19, 1973 [21] Appl. No.: 426,066

[521 U.S. Cl. 30/228 [51 I Int. Cl B26b 15/00 [58} Field of Search 30/379, 198, 296 B, 228, 30/180, 231, 241

[56] References Cited UNITED STATES PATENTS 2,748,476 6/1956 Cooper 30/198 2,751,940 6/1956 Miller 30/228 3,213,605 10/1965 Welden 30/228 3,401,455 9/l968 Gebauer 30/228 3,584,381 6/1971 Jamison 30/228 3,721,004 3/1973 Buckles 30/228 Primary ExaminerAl Lawrence Smith Assistant ExaminerRoscoe V. Parker, Jr. Attorney, Agent, or FirmLimbach, Limbach & Sutton Dec. 17, 1974 5 7 ABSTRACT A portable pruning device which includes a gasoline motor powered hydraulic pump mounted on a sled which is capable of being dragged behind the operator or carried as a backpack, the air for the pump motor being drawn through a chamber in the sled structure to cool the hydraulic fluid which flows through a conduit in the sled structure on one side of the air chamber. In one embodiment a hydraulically actuated shear blade is operatively connected to the pump through hoses and a rotary coupling and is mounted on a modular mast assembly which includes a pair of hollow coaxial pipes rigidly connected together at their ends by a threaded member which is adjustable to put the inner pipe in compression and the outer pipe in tension, relative to each other, thereby forming a rigid, lightweight structure, the inner pipe of the mast assembly carrying the hydraulic fluid to operate the shearing blade.

11 Claims, 11 Drawing Figures PATENTEL I "11914 I 3,854,204

SHEIEI u 05 4 F/G-l/ SELF CONTAINED PRUNING MECHANISM BACKGROUND OF THE INVENTION The present invention relates to a hydraulically operated pruning device and more particularly to a self contained and portable hydraulically operated pruning device.

A primary method in use today for pruning on a large scale involves the use of a tractor drawn pneumatic compressor which feeds a plurality of pneumatically operated pruning devices through connecting hoses. This arrangement has several disadvantages. For example, if the compressor breaks down all of the units are thereby rendered inoperable. Another disadvantage is that none of the pruning device operators can move faster than the slowest operator since all are connected to the same compressor. In order to avoid these disadvantages, there have been numerous suggestions for self contained, portable, hydraulically operated pruning devices.

Typically such devices are only backpack mounted and are not equipped to be dragged along the ground. A number of problems are inherent in the various suggested devices to date. One such problem is that if no provision is made for cooling the hydraulic fluid it has a tendency to become overheated, which results in pump cavitation and also in rapid deterioration of the seals in the device. Another problem is that the mast structure which carries the hydraulically operated shears must be rigid but yet lightweight. In some prior art devices the mast contains a long rod which connects the shears at one end of the mast with a hydraulic cylinder at the other end. Such a rod adds appreciably to the weight of the mast.

Still another limitation on such devices is that the operator must have continuous control over the closing of the shear blades so that the blades may be partially closed when pruning a number of closely spaced grapevines, for example. Other requirements of such self contained pruning devices are that the mast structure which carries the shears must be capable of being completely rotatable with respect to the hydraulic pump without tangling the connecting hydraulic supply hoses.

The mast structure must be easily and quickly adjustable to take into account different pruning tasks such as pruning both relatively low level and relatively high level branches. Furthermore, the mast assembly should be made of modular units which can be easily combined for specified tasks. For example, when pruning high level orange branches the mast may need to be as long as 10 feet and the hook and shearing blade should be angled with respect to the'mast so that the operator can effectively see which branch he is cutting. For low level tasks the mast assembly may only need to be adjustable over a relatively short length, such as a few feet. In still other applications, such as grapevine pruning, for example, it would be desirable to have the blade and hook assembly closely held by the operator with no mast at all. Most present units do not have these convertibility features nor do they have modular construction.

A further requirement is that since the device is likely to be operated by persons having limited technical skills, it must be relatively maintenance free.

SUMMARY OF THE INVENTION The disadvantages of the prior art devices and the above noted requirements are met by the device of the present invention comprising a self contained pruning device having a partially hollow sled, a motor driven hydraulic fluid pump mounted on the sled, a portion of the hollow sled being coupled to the pump to act as a hydraulic fluid reservoir, a hydraulically actuated shear and hook assembly, an assembly of modular units for supporting the hook and shear, at least one of the modular units including inner and outer hollow coaxial tubes, at least one of which is operatively connected to the fluid actuated shear blade, the coaxial tubes being rigidly interconnected at both of their ends, means for placing the coaxial tubes in relative compression and tension, respectively, and control means for selectively providing a fluid path between the pump outlet and one of the coaxial tubes.

In the preferred embodiment, the operator has the choice of carrying the sled mounted motor and pump unit on his back or dragging it behind on the ground. The sled is shaped so as to have an air chamber through which air is drawn by the pump motor. A conduit which is integrally formed in the sled base allows hydraulic fluid to pass back and forth across one side of the air chamber so that the fluid is thereby cooled. This feature allows for long term usage of the mechanism without pump cavitation or undue deterioration of the seals. It also reduces the size of the hydraulic fluid storage tank which is required.

The coaxial tubes are rigidly interconnected at both their ends and a threaded member at one set of ends is adjustable to force the inner coaxial tube longitudinally against the restraining force of the outer coaxial tube so that they are placed in relative compression and tension, respectively. This construction allows for the use of lightweight materials while at the same time maintaining a high degree of strength in the mast assembly. A mast type support assembly can be made up of one or more such modular units of varying lengths which have threaded male and female ends.

A rotary coupling between the pump and the support assembly allows the support assembly to be rotated with respect to the pump without breaking the fluid communication between them. A pair of hydraulic hoses connect the outlet and inlet of the pump through the rotary coupling to a poppet diverter valve which is integrally constructed with the rotary coupling. The hydraulically operated shearing blade is selectively supplied with fluid by the poppet valve, which allows for substantially proportional control of flow of hydraulic fluid from the pump.

The valve normally allows the hydraulic fluid to be circulated through the system at a high flow rate and a low pressure. When the valve is closed to operate the shearing blade, the fluid return line is thereby blocked to reduce the flow rate and increase the fluid pressure between the output port of the pump and shear. This high pressure fluid activates the shear through a hydraulic cylinder. Operating the system normally at a low fluid pressure is a safety feature of the invention because it reduces the danger to the operator of the likelihood of the connecting hoses bursting.

In one embodiment of the invention, a handle which surrounds the mast assembly includes a thumb operated lever which engages with detents on the mast assembly so that it is slidable through the handle thereby allowing the distance of the shear from the handle to be easily and quickly adjusted.

The shear blade and its hydraulic actuator cylinder are normally mounted at the end of the mast assembly furthest from the handle. This structure also adds to the lightweight feature of the construction since the solid connecting rod between the shear blades and the hydraulic actuator can be made very short.

Since the system has a modular construction, the hydraulically operated shear and hook assembly may be detached from the mast support and connected directly to the rotary coupling and diverter control valve unit for closely held work. Furthermore, some modular units of the support assembly are angled to adapt the system for particular tasks, such as clipping branches close to the ground, for example.

It is, therefore, an object of the present invention to provide a lightweight, self contained pruning device.

It is another object of the invention to provide a self contained pruning device which is easily adjustable by an unskilled operator.

It is still another object of the invention to provide a self contained pruning device which is relatively maintenance free.

It is a further object of the invention to provide a self contained pruning device which may optionally be dragged along the ground or carried on the operators back.

It is a still further object of the invention to provide a self contained pruning device constructed of modular units so that the distance and relative angle between the shearing blade and the hand held control unit may be easily converted from one of a plurality of arrangements to another.

The foregoing and other objectives, features and advantages of the invention will be more readily understood upon consideration of the following detailed description of certain preferred embodiments of the invention, taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of the sled, motor and pump unit together with a portion of the mast assemy;

FIG. 2 is a perspective view of the motor, pump and sled assembly depicted in FIG. 1 when mounted in backpack fashion;

FIG. 3 is a perspective view with portions broken away of the hydraulically actuated shear and hook assembly together with a portion of the end of the mast assembly of the embodiment depicted in FIG. 1;

FIG. 4 is an enlarged, perspective view in section of the sled assembly taken generally along the line 4-4 in FIG. 1;

FIG. 5 is an enlarged side view in section of the hydraulic piston of the shear blade and hook assembly depicted in FIG. 3;

FIG. 6 is an enlarged side view, partly in section, of the hydraulic control and rotary coupling unit and of the handle depicted in FIG. 1;

FIG. 7 is an enlarged perspective view in section of a portion of the rotary hydraulic coupling of the embodiment depicted in FIG. 1;

FIG. 8 is an enlarged side view in section of the poppet diverter control valve depicted in FIG. 6;

FIG. 9 is an enlarged side view in section of an elbow adapter for the mast assembly depicted in FIG. 1;

FIG. 10 is a side view with portions broken away and in section of a control handle adapted to fit directly on the hook and shear assembly depicted in FIGS. 3 and 5; and

FIG. 11 is a sectional view taken generally along the line 111l1 in FIG. 10.

DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTS Referring now more particularly to FIGS. I and 3, there is shown a sled assembly 10 connected by a pair of hydraulic hoses l2 and 13 to a mast assembly designated generally 14.

The sled assembly 10 includes a sled I6 on which is mounted a gasoline powered motor 18 which drives a hydraulic pump 20. The gasoline powered motor 18 is supplied with fuel from a gasoline tank 22 which is mounted on one side of the sled 16. The hoses l2 and 13 pass through a metal bracket 24 which is rigidly attached to the center of the sled 16 at one end. The hose I3 is connected to an inlet pipe of a hydraulic fluid tank 26 which is mounted on the other side of the sled 16.

Referring now more particularly to FIG. 4, the sled construction is such that it has a bottom sheet 28 which is of sufficient strength that it will resist wearing when the sled is dragged along the ground. In some embodiments, the bottom sheet 28 is longitudinally ribbed to decrease drag and to add rigidity. The sheet 28 is replaceable when it becomes worn. At opposite edges of the bottom sheet 28 are a pair of

ribs

30 and 32 which support an intermediate sheet 34 in a spaced relationship with the bottom sheet 28. Together the

sheets

28 and 34 and the

ribs

30 and 32 form a hollow air chamber 36 which is open to the atmosphere at the end of the sled furthest from the motor 18. This opening of the air chamber is designated by reference numeral 38. The other end of the air chamber 36 is also connected to the air intake manifold of the motor 18 by an upright channel 40 which is integrally formed in the intermediate sheet 34. The sheet 34 is preferably made of a material which has a high heat conductivity such as copper, for example. 7

An upper layer of metal 42 which has relatively low heat conductivity is attached to the surface of the sheet 34 which faces away from the air chamber 36. The layer 42 is deformed to provide a continuous, serpentine channel 44. The sheet 42 is bonded to the sheet 34 so that together they provide a sealed, continuous fluid passage from the bottom of the hydraulic fluid tank 26 to an opening 46 in the channel 44. The opening 46 is connected through a pipe 48 to the inlet 50 of the pump 20. Thus, air drawn into the engine 18 through the air chamber 36 cools the hydraulic fluid flowing from the tank 26 in the channel 44 to the inlet 50of the pump 20. The outlet 52 of the pump 20 is connected to the hose 12.

The mast assembly 14 is adjustably fitted into a handle 54. In FIGS. 5 and 6 it can be seen that the mast assembly I4 is comprised of an outer tube 56 and an inner tube 58 which is coaxial with the tube 56. The outer tube 56 is provided with a plurality of spaced detents 60 which are engaged by a spring biased thumb latch 62 mounted on the handle 54. The latch 62 and the detents 60 allow the mast assembly 14 to be selectively positioned within the handle 54. The detents are crimped over reinforcing cups 61 which are positioned within the outer tube 56 and which support the inner tube 58. The cups 61 also add to the rigidity of the mast assembly 14.

An interior threaded hollow receptacle 64 is rigidly affixed to the end 66 of the outer tube 56 which is closest to the handle 54. An exteriorly threaded hollow cap 68 is screwed inside the receptacle 64. The cap 68 is provided with an outer O-ring seal 70 which seals against the inner surface of the receptacle 64. The term O-ring seal as used in this specification is to be understood as including the annular groove in the supporting member in which the O-ring is retained. The hollow of the cap 68 is also provided with an inner O-ring seal 72 which seals about the end 74 of the inner coaxial pipe 58 which is closest to the handle 54.

A plug 76 is firmly attached to the opposite end of the outer coaxial pipe 56 and is provided with an interior throughbore 78 which connects with the hollow pipe 58. The plug 76 is sealed to a corresponding end 80 of the inner coaxial pipe 58 by an O-ring seal 82. The end of the pipe 80 bears against a shoulder 84 in the bore 78. Thus, when the cap 68 at the handle end of the pipes is rotated in the proper direction, it exerts a compressive force on the pipe 58 which bears against the shoulder 84. The reactive force transmitted through the receptacle 64 and the plug 76 to the outer pipe 56 places it in tension. Thus, the inner pipe 58 is in relative compression and the outer pipe 56 is in relative tension so that they form a rigid structure without the necessity of high density, heavy materials.

A threaded plug 86 is engaged in the receptacle 64 adjacent to the cap 68. The plug 86 has an O-ring seal 88 which bears against the inside surface of the receptacle 64. The plug 86 also has an interior bore 92 in the cap 68. The

bores

90 and 92 thus provide a fluid passage to the hollow end 74 of the inner tube 58. The bore 90 is connected by a hydraulic hose 93 to a hollow plug 94 threaded into the handle 54. A fluid passageway 96 connects plug 94 to an enlarged bore 98 in the handle 54.

A hydraulic control unit for selectively controlling the hydraulic fluid flow to the mast assembly 14 has a main body portion 100 and a neck portion 102 which is threadably engaged in the bore 98. A through-bore 104 in the neck portion 102 provides fluid communication between the bore 96 and a poppet valve 106 contained within a chamber 116 in the main body portion 100. Referring now more particularly to FIG. 8, the poppet valve 106 is cylindrical and has a cone shaped upper end 108 and a lower enlarged end 110, as viewed in FIG. 8. The valve 106 also has a bore 112 which receives a pointed end of a valve metering pin 114.

The valve pin 114 passes out of the chamber 116 and the main body 100 through an O-ring seal 118. An L shaped lever arm 120, pivoted at one end to the main body 100, bears against the pin 114 to act as a trigger for the valve. The bore 112 has a portion 119 which is reduced in diameter at the tip of the cone shaped valve end 108. The pointed end of the valve pin 114 seats in this reduced bore 119 when the valve pin is pushed as far into the chamber 116 as possible. The wall of the chamber 116 directly opposite the valve end 108 is tapered to form a valve seat 121 for the valve end 108. The valve seat 121 is connected to a fluid by-pass passage 122 in the main body 100 which connects with the inlet of the pump 20. The chamber 116 is also connected with

fluid passages

104 and 124 which are on opposite sides of the valve 106. The trigger pin 114 controls the balance of the hydraulic fluid force acting on the poppet valve 106 in a manner known to those skilled in the art.

Hydraulic fluid under pressure enters the chamber 116 from the pump 20 through the inlet passage 124 and returns to the pump 20 through the bypass passage 122. When the valve pin 114 is fully inserted into the chamber 116 and the poppet valve end 108 is fully engaged with the valve seat 121, as shown in hidden line fashion in FIG. 8, the fluid by-pass passage 122 is cut off and the pressurized fluid is diverted through the outlet passage 104, passage 96, the hose 93 and the hollow interior mast pipe 58 to actuate a cutting shear 154 as will be explained in greater detail hereafter. A governor (not shown) on the motor keeps the motor speed constant as the pump requires more power to build up the high fluid pressure. A self-limiting pump, or in some embodiments, a pressure sensitive by-pass valve (not shown) between the inlet and outlet ports of the pump, protects the system from developing too high a fluid pressure. The hydraulically balanced valve 106 permits continuous control, that is proportional closing of the shear blades, which is important for pruning such things as. individual grape vines which are bunched close together and are of a small diameter.

The

passageways

122 and 124 connect with a large bore or recess 126 in the main body 100. A rotary coupling assembly 128 is fitted within the bore 126. The coupling assembly 128 has a cylindrical body portion 130 which has a fluid passage 132 connecting the threaded end of the hose 12 with the passageway 124. The coupling body 130 also has a passageway 134 which connects the passage 122 with a threaded end of the hose 13.

Referring now more particularly to FIG. 7, it can be seen that the end of the body 130 which is furthest within the bore 126 has a reduced neck portion 136 which is fitted with an outer, channel shaped rotary seal 138. The seal 138 bears against a recess in the bore 126 to prevent the pressurized fluid in the passageway 132 from leaking into the main portion of the bore 126. A groove 140 in the coupling body 130 surrounds the neck 136 and is connected to the passage 134. The groove is located with respect to the rotational axis of the coupling body 130 such that for any rotational position of the coupling body 130 relative to the main body 100 the end of the passage 122 is opposite the groove 140, thereby providing fluid communication between the passage 134 and the passage 122. Also any leakage of hydraulic fluid from the seal 138 will be collected in the surrounding groove 140 and be returned to the pump inlet 50 through the hose 13.

A bearing assembly 142 located between the groove 140 and the exterior end of the coupling body 130 supports the coupling body 130 in the bore 126. Surrounding the coupling body 130 between the bearing assembly 142 and the exterior end of the coupling body 130 is a rotary seal 144 fitted against a stationary collar 146 which also surrounds the body 130. An O-ring seal 148 is fitted in a recess about the outer surface of the collar 146 to provide a low pressure seal between it and the interior surface of the recess 126.

The coupling body 130 is provided with a shoulder 150 between the groove 140 and the bearing assembly 142. The shoulder 150 presses against the bearing assembly 142 which in turn presses against the collar 146. A retaining ring 152 fitted in a groove in the outer edge of the recess 126 bears against the collar 146 and thus retains the whole coupling assembly 128 within the recess 126.

Referring now more particularly to FIGS. 3 and 5, a shear blade 156 is pivotally mounted on a hook 154 attached to one end of a hydraulic cylinder casing 158. The outer end of the casing 158 is threaded onto the plug 76 in the upper end of the outer mast pipe 56. The blade 156 and the hook 154 each have sharpened scissor-like edges for cutting limbs, as best illustrated in FIG. 3. The blade 156 is attached by a pair of linking members 160 to one end of a connecting rod 162 which projects from inside the hydraulic cylinder 158. The other end of the connecting rod 162 is fitted with a pair of spaced apart piston heads 164 and 165 which are carried within a bore 166 in the cylinder 158. An ring seal 168 is positioned between the piston heads 164 and 165 to seal with the interior surface of the bore 166. An O-ring seal 169 about the plug 76 seals it against the cylinder bore 166 to close off its open end.

A spring 170 which is coaxial with the connecting rod 162 is pressed between the closed end of the bore 166 and the piston head 164 so that the piston head 165 is normally pressed against the plug 76. When fluid under high pressure is pumped through the inner coaxial tube 58 and the plug bore 78, as described above, a fluid force is exerted against the piston head 165 to overcome the restraining force of the cylinder 158. The extension of the connecting rod 162 pivots the blade 156 in a manner such that the sharpened edges of the hook 154 and the blade 156 close and cut an object positioned between them.

In the above described embodiment, the materials of certain of the elements have not been described in de tail since they necessarily will depend on the use to which the pruning device is put. In general, the materials should be strong but lightweight,such as aluminum or certain types of plastic materials. In situations where the pruning device is to be used around electrical power lines, the mast assembly or the top portion thereof at least should be made of non-electrically conductive material.

In operation, the user holds the mast assembly 14 by the handle 54. By depressing the thumb latch 62 the position of the mast assembly 14 in the handle 54 can be adjusted. The cutting blade 156 is actuated by squeezing the lever 120. The sled assembly may be dragged behind the operator and in some embodiments is connected to the hydraulic control actuator assembly by a cable 172 which is shorter than the length of the

hydraulic hoses

12 and 13 so as to relieve them of any strain in pulling the sled assembly 10. In situations where dragging the sled assembly 10 is not preferable, it may be mounted on a frame 174 by snap-latches 176. A harness 178 is attached to the frame 174 so that it may be slipped over the shoulders of the operator.

Since the mast assembly 14 is constructed of modular units which may be substantially identical at their end portions it is possible to interchange a number of modular units in the mast assembly in order to obtain any of various lengths or angles between the blade 156 and the control unit 100. Referring now more particularly to FIG. 9, one such modular unit, in the form of an elbow adapter 180 for the mast assembly 14, is illustrated. The body portion of the elbow 180 is bent at an angle and is provided at one end with a threaded female receptacle 181 to receive the end plug 76 of the mast assembly 14 in substantially the same manner as the female end of the hydraulic cylinder casing 158 de-- scribed above in reference to FIG. 5. The opposite end of the body portion of the elbow 180 is substantially identical to the male portion 76 of the mast assembly 14 and includes a threaded male plug portion 182 which carries an external circumferential O-ring seal 184 which seals the plug portion 182 against the cylinder bore 166, for example. The elbow body 180 contains a through bore 186 to carry the pressurized fluid to act upon the piston head 165.

The insertion of the elbow 180 into the mast assembly 14 allows the operator of the pruning device to more easily view the cutting blade. In other arrangements the elbow might be inserted at the handle end of the mast assembly or even at its midpoint depending on the particular application to which the pruning device is put. For example, the elbow 180 allows the operator to stand erect when using the pruning device to cut roots close to the ground. It will be understood, of course, that the particular angle depicted for the elbow 180 in FIG. 9 is purely exemplary and in other embodiments other angles may be utilized. Since the unit is by draulically operated there are no mechanical limitations on the degree of bend in the elbow. Furthermore, although only a single modular element is depicted for the mast assembly 14 in FIG. 3, in other embodiments other lengths of the mast assembly may be substantially identical to the portions shown in FIGS. 3 and 5.

Since all of these modular units are equipped with substantially identical male and female ends, they may be readily and easily interconnected. One advantage of the invention in having the hydraulic actuator immediately adjacent to the cutting is that no complicated mechanical linkage is required between the control handle and the cutting blades. Only a single hydraulic fluid carrying passage need be provided.

Referring now more particularly to FIG. 10, in still another modification of the pruning device depicted in FIG. 1 the mast assembly is eliminated altogether and the control handle and rotary coupling unit has its threaded neck portion 102 directly engaged in the threaded female end of the hydraulic casing 158. The L-shaped lever arm is replaced with a substantially straight lever arm 188 which is pivotally mounted to the body 100 so as to act against the valve pin 114. A trigger guard 190 is fitted closely about the exterior surface of the bottom of the hydraulic casing 158 and is attached to it by a plurality of screws 192 which are threaded into the exterior surface of the hydraulic casing 158. The trigger guard 190 has a relieved portion 192 so that the operator can squeeze the lever 188 into a position substantially parallel with the longitudinal axis of the hydraulic casing 158 as is illustrated in dashed line fashion in FIG. 10.

In this modified embodiment of the invention, the operator may closely hold the cutting shear of the pruning device when trimming such things as grape vines, for example. Because the body 100 contains not only the control valve but also the rotary coupling 128, the operator need not be concerned with twisting of the hoses l2 and 13.

The term fluid as used herein is preferably meant to pertain to a liquid, however, in some less advantageous embodiments the device may be operated pneumatically. Such embodiments are less advantageous at the present time because they require a greater amount of energy to operate due to the compressibility of the gas. Nevertheless, it is within the spirit and scope of the invention to operate the self contained pruning device described herein with such fluids as air or steam, for example.

Although in the above embodiments a hook and shear blade assembly is described, in other embodiments other types of cutting devices, such as a pair of movable cutting blades, for example, may be utilized. In still other embodiments, the fluid actuated device may be other than a cutting device, such as, for example, a stapler for attaching grapevines to their support poles.

The terms and expressions which have been employed here are used as terms of description and not of limitation, and there is no intention, in the use of such terms and expressions, of excluding equivalents of the features shown and described, or portions thereof, it being recognized that various modifications are possible within the scope of the invention claimed.

1 claim:

1. A self contained, power operated device comprising a partially hollow sled, a motor mounted on the sled, a fluid pump having inlet and output ports and being mounted on the sled and powered by the motor, a first portion of the hollow sled being coupled to the pump to act as a fluid reservoir, a fluid actuated device, a mast assembly for supporting the fluid actuated device, the mast assembly having inner and outer coaxial tubes at least one of which is operatively connected to the fluid activated device, and control means for selectively providing a fluid path between the pump and the coaxial tubes such that one of the coaxial tubes is operatively connected to the pump, the coaxial tubes being rigidly interconnected at both at their ends and means for placing the coaxial tubes in compression and tension relative to each other.

2. A self contained, power operated device comprising a partially hollow sled, a motor mounted on the sled, the motor having an air intake manifold, 21 fluid pump having inlet and output ports and being mounted on the sled and powered by the motor, a first portion of the hollow sled being coupled to the pump to act as a fluid reservoir, a second portion of the sled being a hollow air chamber having an opening at one end and being connected to the air intake manifold at the other end so that air is drawn through the chamber by the motor, the air chamber being located adjacent to the first portion of the hollow sled so as to provide cooling for the fluid therein, a fluid actuated device, a mast assembly for supporting the fluid actuated device, the mast assembly having inner and outer coaxial tubes at least one of which is operatively connected to the fluid actuated device, and control means for selectively providing a fluid path between the pump and the coaxial tubes such that one of the coaxial tubes is operatively connected to the pump outlet, the coaxial tubes being rigidly interconnected at both of their ends and means for placing the coaxial tubes in compression and tension relative to each other.

3. A self contained, power operated device as recited in claim 2 wherein the control means includes a poppet valve having. inlet and outlet ports, a by-pass port, a hollow valving member for selectively closing off the by-pass port, and a metering pin slidable within the valving member for actuating it, and means for rotatably coupling the inlet and by-pass ports of the valve with the outlet and inlet ports of the pump, respectively, and for coupling the by-pass part of the valve with the one coaxial tube.

4. A self contained, power operated device as recited in claim 3 wherein the rotary coupling means includes a main body portion having a bore in one end and a pair of first and second fluid passages which connect the bore to the inlet and by-pass ports of the valve, respectively, the first passage exiting into the main body bore at a first point located along a central axis of the bore in the main body portion and the second passage exiting into the bore at a second point radially spaced from the first point, a coupling body, means for supporting the coupling body within the main body bore so that the coupling body may be rotated about the central axis, the coupling body having a third fluid passage which has an exit within the main body bore directly opposite to the first point, an annular groove centered about the central axis of the bore and in fluid communication with the second passage and a fourth fluid passage connected with the annular groove, means for providing a high pressure rotary seal between the annular groove and the bore exits of the first and third fluid passages, means for providing a low pressure rotary seal between the annular groove and the exterior end of the main body bore and means for connecting the third and fourth fluid passages to the outlet and inlet ports of the pump, respectively.

5. A self contained, power operated device as recited in claim 2 further comprising a handle for the mast assembly, the handle surrounding a portion of the outer coaxial tube and providing a slidable support therefor, the outer tube having longitudinally spaced detents in its outer surface and a spring biased latch mounted on the handle and engagable with the spaced detents for I selectively positioning the mast assembly with respect to the handle.

6. A self contained, power operated device as recited in claim 2 wherein the fluid operated device includes a movable shear blade pivotably mounted on the mast assembly at one end thereof and a fluid operated cylinder and piston assembly mounted at the same end of the mast assembly as the shear blade, the piston being connected to the shear blade and the cylinder being operatively connected to the one coaxial tube for pivoting the shear blade in response to the pressure of the fluid from the pump.

7. A self contained, power operated device as recited in claim 2 further comprising a backpack frame, a harness for the backpack frame and means for removably mounting the sled, motor and pump as a unit onto the frame.

8. A self contained pruning device comprising a partially hollow sled, a motor having an air intake manifold and being mounted on the sled, a fluid pump having inlet and output ports and being mounted on the sled and powered by the motor, a first portion of the hollow sled being coupled to the pump to act as a fluid reservoir and a second portion of the sled being a hollow air chamber having an opening at one end and being connected to the air intake manifold at the other end so that air is drawn through the chamber by the motor, the

air chamber being located adjacent to the first portion of the hollow sled so as to provide cooling for the fluid therein, a fluid actuated shear blade, a modular support assembly for supporting the shear blade, and control means for selectively providing together with the modular support assembly a fluid path between the pump and the fluid actuated shear blade such that the fluid actuated shear blade is operatively connected to the pump outlet.

9. A self contained pruning device as recited in claim 8 wherein the modular support assembly includes interchangeable units having a plurality of lengths and at least one elbow member.

10. A self contained pruning device as recited in claim 9 wherein at least one of the interchangeable units includes inner and outer coaxial tubes at least one of which is operatively connected to the shear blade, the coaxial tubes being rigidly interconnected at both of their ends and means for placing the coaxial tubes in compression and tension relative to each other.

11. A self-contained pruning device as recited in claim 8 wherein the fluid actuated shear blade includes a hydraulic actuator for moving the shear blade in response to the supply of fluid under pressure from the control means and wherein the modular support assembly includes a handle attached directly to the hydraulic actuator, the control means being operatively engaged with the fluid actuator and further including means for providing a rotary, fluid coupling between the control means and the pump.

Claims

2. A self contained, power operated device comprising a partially hollow sled, a motor mounted on the sled, the motor having an air intake manifold, a fluid pump having inlet and output ports and being mounted on the sled and powered by the motor, a first portion of the hollow sled being coupled to the pump to act as a fluid reservoir, a second portion of the sled being a hollow air chamber having an opening at one end and being connected to the air intake manifold at the other end so that air is drawn through the chamber by the motor, the air chamber being located adjacent to the first portion of the hollow sled so as to provide cooling for the fluid therein, a fluid actuated device, a mast assembly for supporting the fluid actuated device, the mast assembly having inner and outer coaxial tubes at least one of which is operatively connected to the fluid actuated device, and control means for selectively providing a fluid path between the pump and the coaxial tubes such that one of the coaxial tubes is operatively connected to the pump outlet, the coaxial tubes being rigidly interconnected at both of their ends and means for placing the coaxial tubes in compression and tension relative to each other.

3. A self contained, power operated device as recited in claim 2 wherein the control means includes a poppet valve having inlet and outlet ports, a by-pass port, a hollow valving member for selEctively closing off the by-pass port, and a metering pin slidable within the valving member for actuating it, and means for rotatably coupling the inlet and by-pass ports of the valve with the outlet and inlet ports of the pump, respectively, and for coupling the by-pass part of the valve with the one coaxial tube.

5. A self contained, power operated device as recited in claim 2 further comprising a handle for the mast assembly, the handle surrounding a portion of the outer coaxial tube and providing a slidable support therefor, the outer tube having longitudinally spaced detents in its outer surface and a spring biased latch mounted on the handle and engagable with the spaced detents for selectively positioning the mast assembly with respect to the handle.

8. A self contained pruning device comprising a partially hollow sled, a motor having an air intake manifold and being mounted on the sled, a fluid pump having inlet and output ports and being mounted on the sled and powered by the motor, a first portion of the hollow sled being coupled to the pump to act as a fluid reservoir and a second portion of the sled being a hollow air chamber having an opening at one end and being connected to the air intake manifold at the other end so that air is drawn through the chamber by the motor, the air chamber being located adjacent to the first portion of the hollow sled so as to provide cooling for the fluid therein, a fluid actuated shear blade, a modular support assembly for supporting the shear blade, and control means for selectively providing together with the modular support assembly a fluid path between the pump and the fluid actuated shear blade such that the fluid actuated shear blade is operatively connected to the pump outlet.