US 3219129 A
Description (OCR text may contain errors)
Nov. 23, 1965 SAKUJI YAMADA 3,219,129
WORKING DEVICE PORTABLE ON THE OPERATORS BACK Filed March 15, 1963 4 Sheets-Sheet 1 Nov. 23, 1965 SAKUJl YAMADA WORKING DEVICE PORTABLE ON THE OPERATOR'S BACK 4 Sheets-Sheet 2 Filed March 15, 1965 FIG. 3
WORKING DEVICE PORTABLE ON THE OPERATOR'S BACK 4 Sheets-Sheet 3 Filed March 15, 1963 FIG.?
Nov. 23, 1965 SAKUJI YAMADA 3,219,129
WORKING DEVICE PORTABLE ON THE OPERATOR'S BACK 4 Sheets-Sheet 4 Filed March 15, 1965 viii/III, ---u I ""IIIIIIIIIIIIIII FIG. 9
United States Patent 3,219,129 WORKING DEVICE PORTABLE ON THE OPERATORS BACK Sakuji Yamada, 1 Aza Okunishiyama Kuruma, Sumaku Kobe, Japan Filed Mar. 15, 1963, Ser. No. 266,155 4 Claims. (Cl. 17330) This invention concerns a device which is carried on an operators back. It includes a prime mover as a power source, for example an internal combustion engine, which drives a covered steel wire of about two meters length, carrying at its tip a controllable work performing tool. The point of application of the tool is controlled by the hand or hands of the operator, and the tool performs such work in the lumber industry as mowing down bushes, cutting branches, and felling trees; while in the transportation industry it performs such diverse work as cleaning or removing or grinding off encrusting materials or rust, from the hulls of ships or the chassis of land vehicles.
A primary object of invention for this type of machine, is a low gross weight, including a low weight of the engine. If it substantially exhausts the operator, merely to mount the machine on his back and to transport the same, then his useful capacity to perform tasks with the machine is practically zero. It is therefore clear that the lighter the weight of the equipment, the greater will be the useful capacity of the operator to perform useful tasks in addi tion to the carrying and transporting.
A second object of invention, as the machine is operated on the operators back, is to reduce the vibration and shock, transmitted to the body, and therefore consideration must be given to the uniform and nonuniform forces generated by the machine and the damping of such forces before they reach the operator. With existing machines, when back-carried and operating for as short a time as thirty minutes, the hands and shoulders of the operator are numbed and insensible, and work must be immediately discontinued,
A third object of the invention is for the operator to be able to change the direction or orientation of the tool or rotor as will while operating. This change is necessary because all surfaces worked upon are not plane, and the work performing rotor, as a discoid cutter, or brush or grinder, as each is moved along, should always be kept parallel with the slope of the undersurface, whether such surface is a mountain, or the uneven surface of hollow land, or the surface of a tortuous foot path, or even a curved surface in the outer plating or covering of a boat hull.
The fourth object of the invention is in ease of replacement of the tool or rotor, and ease of assembly and disassembly of each element making up the machine.
Further objects of the invention will be made apparent throughout the following description of the invention.
In the drawings,
FIGS. 1 and 2 are respectively an elevation and a plan view, showing a use of the device of this invention when mounted on the operators back for performing work approximately at ankle level;
FIG. 3 is a side view showing particularly the fitting frame, engine and shoulder straps; the dashed line at the left of the figure denoting a part outline of the back of the operator;
FIG. 4 is a front view of the structure of FIG. 3;
FIG. 5 is a plan view of the structure of FIG. 3 taken along line 5-5 of FIG. 3 and looking in the direction of the arrows;
FIG. 6 is a cross section of a pivoting bearing taken along the line of 66 of FIG. 4;
FIG. 7 is an enlarged assembly view of the power takeoff, the flexible drive shaft, the Work performing rotor Patented Nov. 23, 1965 "ice (illustrated by a disc cutter) and the controls for the fuel valve and the belt tightener clutch;
FIG. 8 is a cross section of the connecting mechanism between power takeoff pulley 10 and the upper flexible portion of the drive shaft taken along the line 88 of FIG. 7;
FIG. 9 is a cross section of the linking mechanism between the upper flexible portion and the central inflexible portion of the drive shaft taken along the line 9-9 of FIG. 7;
FIG. 10 is a detail view partly in section of the flexible covering F which surrounds the core of the drive shaft;
FIG. 11 is a cross section of the linking housing between the work performing rotor and the lower end of the flexible shaft taken along the line 1111 of FIG. 7;
FIG. 12 is a cross section through a handle and its fastening means.
In FIG. 1, E denotes an internal combustion engine fixed 0n the operators back with a fitting frame, A denotes a discoid cutter for mowing weeds, F denotes a flexible metallic pipe covering the whole length of a steel wire rope W of about two meters in length which connects the power output pulley 10 of engine E and the discoid cutter A; P and P denote concentric inner and outer inflexible metallic pipes, collectively forming a director cover and covering the flexible metallic pipe F for about one meter at its middle part between the power output pulley 10 of engine E and the discoid cutter A; H and H denote handles projecting on the inflexible metallic pipes P and P and R denotes a connecting rod between an exterior arm of the linking mechanism and the exterior metallic pipe P The handles H and H approaching or receding from each other or changing the relative angle made by them, perform their work to change the direction of the tool A at will.
FIGS. 3, 4, 5 and 6 show the fitting frame of the engine E. Numeral 1 denotes in each figure the outer frame showing its side in a shape of the letter L, with a ribbon plate projecting horizontally at the middle of the upper end of the principal framework made of bent pipe; numeral 2 denotes an elastic pad fitted on the back of the outer frame 1; numeral 3 denotes belts for supporting the frame from the shoulders fitted to the end of the horizontal ribbon plate on the outer frame 1 and to either corner of the lower part, and with the belts the outer frame 1 is directly supported on the operators back. The inner frame composed of the framework 4a is made of a pipe rectangularly bent with upper and lower projecting ribbon plates 4b, carries the base of the engine E which is firmly fixed to the inner frame with bolts 5 shown in FIG. 4 while the upper and lower ribbon plates 4b are respectively bent horizontally at tip with the upper tip pivoted to the ribbon plate 1a of the outer frame 1 with a pin 6 and the lower tip pivoted with an upright pin 8 on the cross beam 1b of the outer frame with an antifriction bearing supported on a rubber sea-t 7 between the tip of the ribbon plates 4b and the antifriction hearing as shown in FIG. 6. The engine E fixed to the inner frame which is pivotally supported with the upper pin 6 and the lower pin 8 respectively in the outer frame 1. When the frame 1 is supported on the operators back by belts 3, the engine and the inner frame as a unit are capable of turning movement. Numeral 9 denotes a pulley attached to the projecting main shaft of the engine E at the rear part of the inner frame, and 10 denotes another pulley connected to the pulley 9 by a driving belt 11 with the shaft for pulley 10 supported by an embraced bearing 12 (-FIGS. 3 and 5) at the lower end of the inner frame. The other end jutting out from said bearing 12 (FIG. 8) is connected by linking mechanism with the tip of the driving flexible cable or core W. The full explanation of the linking mechanism and the driving shaft comes later. Numeral 13 denotes the roller for engaging and disengaging the belt 11, and 14 denotes a pivoted rod for rotatably supporting the roller 13 at the free end with its base pivoted to a crosspiece in the middle of the main body of the inner frame 4b, and it is so devised as to be pulled by a spring in the direction of disengaging the belt 11 and, when a control wire 36 is pulled, the revolving wheel 13 is drawn toward the belt 11, thus tensioning the belt to drive pulley 10 from pulley 9.
The characteristics of the construction of the above mentioned fitting frame lie in these three points: that the inner frame is pivoted to the outer frame 1 with two points, upper point 6 and lower point 8, in such a way that it is capable of turning. The driving wire rope W is made to extend away from the operators back from the inner frame, so that when the engine E is put on the operators back, the flexible cable driving rope, as shown in FIG. 2, at its power input end extends rearwardly from the operators back and then bends gently curves to his front; and that a slack take up mechanism of the belt is capable of controlled slipping.
Since the inner frame of the fitting frame is pivoted to the outer frame 1 at two points, 6 and 8 one upper and one lower, the vibration of the engine E is balanced at said upper and lower pivot points, and the vertical vibration is deadened by the rubber seat 7, thus considerably reducing the vibration conveyed to the operators shoulders and hands. When the internal combustion engine alone is put on the ground and set in motion, it looks as if it were jumping about due to its own vibration, but when it is fitted to the frame of this invention and set in motion, it conveys only the smallest amplitude of vibration to the frame and does not show any of such phenomenon of jumping about. When, for example, this supporting point on one side is changed to two to four points instead of one point as seen in this invention, the phenomenon changes completely and it observed that the frame itself is violently vibrated, so it is considered a main point in damping or killing the effect of the vibration of the engine to support it at the upper and lower pivot points. The engine is pivotally mounted so as to be capable of turning independently of the outer frame 1, and the driving rope W is designed to be flexible to lead to the operators front from the back of the inner frame 4, resulting in the advantage of making the change of direction or orientation of the work tool without much effort. If is well understood from FIG. 2 that as the flexible driving shaft leads to the operators front by way of his side in a gentle curve, the tool can be turned horizontally in as large an extent as 180 in front of the operator without sharply bending the middle of the flexible shaft. In case the position of the tip of the driving shaft is opposite to that shown in the illustration, (that is, extending towards the operators back instead of away from it), the extent of the pivoting or turning angle of the engine is narrowed, and at some angle of turn of the engine, the tool can not be directed to the proper position without sharply bending the flexible shaft. The belt slack take up mechanism 13, 14, 36 permits belt-pulley slipping between the engine main shaft and the power take-off drive shaft. When an unusually excessive resistance is given to the tool, as when the discord hits on soil or stones in the working or mowing of weeds, the machine accommodates this unusual load by belt slippage.
The pulley 10, the bearing 12 shown in FIG. 3, and the flexible metallic pipe F, the inflexible metallic directorcover pipes P and P the handles H and H the tool A and the connecting rod R shown in FIGS. 1, 2 and 7 provide the drive and control for the tool. This driving axle or shaft is composed of the metallic (usually steel) wire rope W as its main inner and core constituent covered, as a protection by the flexible metallic pipe F along the whole length. Inflcxible metallic pipes P and P further cover the exterior part of the mid-portion of the flexible metallic pipe F, serving at once as a director or controller, and as a reinforcement.
The first characteristic of the driving shaft of this invention, is that between the outer periphery of the steel wire rope W and the inner periphery of the flexible metallic pipe F is an extremely small clearance gap so the parts are almost touching each other. Of the driving shafts hitherto well known of which the steel wire rope is a core constituent, the steel wire rope is covered with the flexible metallic pipe, whose inside diameter, however, is, as a rule, several times as large as the outside diameter of the steel wire rope W. For instance, where the steel wire rope W is 10 mm. in outside diameter, the flexible metallic pipe F is to mm. in diameter and is adapted to strengthen the steel wire rope. This is for the design purpose of lowering the rate of snapping of the steel Wire rope, keeping it in its original straight line condition thus preventing the ends of the steel wire rope enclosed by a thick walled pipe and big in diameter, from approaching each other. However, as a steel wire rope, when given a big torque, is twisted in a shape of a spiral, the action arises that both ends of the wire approach each other. This spiral twisting with approaching ends naturally results in a snapping of the wire at the point where the curvature is greatest. Also when this thick prior art flexible metallic pipe is curved, the driving shaft besides being heavy in weight, does not bend easily and in practice a small diameter steel wire rope is chosen as the core of a driving shaft for use with a large inside diameter flexible tube.
In this invention, if the outside of the steel wire rope W is determined to be 8 mm, the flexible metallic pipe chosen may be less than 9 mm. in its inside diameter. Owing to this, not only the Weight is considerably lessened, but greater strength results due to greater relative diameter of the steel Wire rope, which reduces the stress below that of the above discussed prior art, and the objects of this invention are ensured. In other words, as the inside diameter of the flexible metallic pipe F circumscribes the periphery of the steel wire rope W with ever so small a gap between them, the circumscribing metallic pipe F performs as a support, similar to that of any bearing which is made to support the steel wire rope W. The metallic pipe F hitherto in common use is, due to its inflexibility quite different in nature from flexibility of the present invention and is necessary to prevent the steel wire rope from being twisted by the excessive rotation. The flexible metallic pipe F of this invention is constructed so each section of the pipe becomes a bearing for the steel wire rope, and the pipe F cooperates at these sections to prevent excessive rotation while it also performs the function of support without excessively reducing its flexibility.
The flexible metallic pipe F, as it functions in this invention as mentioned above, has a strong structure, as shown in FIG. 10, with coiled piano wire 32 in the shape of a spiral as an inner layer, and ribbon steel wire 33 of nearly a triangular cross section coiled in the shape of a spiral inserted from the outside between the interstice 0f the spiral piano wire 32. In the instance of this invention, when the internal combustion engine on the operators back is of a capacity of 1.2 hp., the steel wire rope is 8 mm. in diameter and the flexible metallic pipe is about 36 mm. in outside diameter.
The second characteristic of the driving shaft of this invention is that the middle part of the flexible metallic pipe F is covered with hard and inflexible double metallic telescoping and relatively rotatable pipes P on the interior and over the flexible tube F and P on the exterior. The driving shaft from the engine E on the operators back to the tool A has a desirable length of about 2 meters. A flexible driving shaft which is as long as 2 meters is inconvenient to handle, and where there is no necessity for turning the direction of the tool A, an inflexible driving shaft may be used as it is not only more convenient to handle, but also serves as reinforcement. In FIG. 7, the periphery of the middle part of the metallic pipe F, excepting the part 60 cm. to 80 cm. from the pulley and the part 30 cm. to 50 cm. from the tool A, is covered with the infllexible metallic pipe P which is covered with the other inflexible metallic pipe P which is shorter in length than said inflexible metallic pipe P The inflexible metallic pipe P is firmly fixed at its top end to the flexible metallic pipe F, and the exterior pipe P slides on the interior pipe P P is also capable of turning with respect to P and is connected at its lowest or distal end to an integral arm IA on the bearing housing of the tool A through the medium of the connecting rod R. The tool A may be widely changed in direction or orientation, as from a coaxial position (right dashed position in FIG. 7) to a back turned position (left dashed position A in FIG. 7), by merely manually sliding the exterior pipe P axially along the in terior pipe P It is observed from this FIG. 7 that the respective planes containing the cutter discs in the two dashed line positions in FIG. 7 are approximately 135 degrees apart. The tool in the positions A and A is made to turn in direction tridimensionally by turning or rotating the handle H with respect to the handle H as H is nonrotatably mounted on P Accordingly, when a horizontal change of direction of the tool shown in FIG. 2 and the tridimensional change of direction shown in FIG. 7 are combined, the tool can be turned in any direction at will. As for the covering position of the pipe P the comparatively long part of 60 to 80 cm. on the side of the engine is left flexible uncovered with the metallic pipe P and the uncovered flexible part, as well understood in FIG. 2, is necessary for the driving shaft to come out to the operators front, from his back, passing round his side in a large arc. If this 60-80 cm. part is too short, it becomes impossible for the tool A to turn direction to a wide extent, and if the pipe of the driving axis bends here through a large total angle and with a small radius of curvature, it causes the steel wire rope to break down. To prevent this sharp bending of the pipe through a small radius of curvature, an espeically strong spring S is provided to this part, wound with small pitch over the flexible metallic pipe F as shown in FIG. 7, and this is the device which prevents too sharp bending without loss of desired flexibility.
The part of the drive which is 30 to 50 cm., located adjacent the tool A is left uncovered, with the end of the flexible metallic pipe P determining the minimum length necessary to allow the tool A to turn direction, by sliding motion of the exterior metallic pipe P over P FIG. 8 and FIG. 11 show respectively, the connecting mechanism for the stub shaft of the pulley 10 with one end of the steel wire rope W, and the linking mechanism for the shaft 21 of the tool A with the other or digital end of said steel wire rope W. Each figure also shows appropriate attaching structure for a respective end of the flexible pipe F. Both structures are almost similar in operation: loosen the fastener 22 by turning back the screw and pull the steel wire rope W and the flexible metallic pipe F apart, and the holder 24 provided with a slot 23 binding the periphery of the pipe F becomes loosened at the tip and the pipe F comes off the holder 24 and at the same time the end piece 25 of the steel wire rope W slips out of the coupling device 26, thus disassembly is simple and quick.
Considering the above mentioned pulley 10 or the tool A, when the nut 27 is backed off, the pulley 10 or the tool A can be removed from the respective bearings 28. In FIG. 11, 29 and 30 denote upper and lower holders, which hold the discoid cutter A when it is used for mowing weeds, and they are respectively provided with a slanting surface, the slanting surface of the lower holder 29 for avoiding the shock from stones in the earth and that of the upper holder 30 for preventing the root of weeds from winding round between the bearing 28 and the discoid cutter A.
FIG. 12 shows the construction whereby the handle H or H is adjustably fitted to the inflexible metallic pipe P or P When the handle H is screwed in, a contact piece 31 presses the outer surface of the pipe P hard enough to settle it into place, and when the handle H is loosened a little, the contact piece 31 loses contact with the outer surface of the pipe P and the pipe P can freely be slid over P As shown in FIG. 7, the handle H is put on the pipe P employing the shorter pipe P in the same construction as that of the handle H so that the position of the handle H can be moved on the pipe P and it is for adjusting the distance between the handles H and H which are gripped each with one of the operators hands while he is operating, as too long or too short an interval makes the operation diflicult.
Element 22' appearing in FIGS. 7 and 9 denotes a fastener of the same construction as that of fastener 22 shown in FIG. 8, and described above.
Element 22" is an interposed pipe which at one end (the right end in FIG. 9) threadedly (40) receives the top end of inflexible pipe P and at the other end (the left end in FIG. 9), frictionally binds the periphery of the flexible pipe F. The binding action results from the compressing and closing action by the slot in the other end of the interposed pipe, caused by threading fastener 22 along 22" until the banded inside of 22' engages the tapered end of pipe 22". Inflexible pipe P' is thus held against movement along the drive structure, but it is able to turn by threading action.
This invention is not limited to cutting as by use of the discoid cutter tool here illustrated, and other types of cutters may be used. Also the invention may be used for grinding when a grindstone or reamer or drill is used as the work performing tool. Also it may be used for cleaning and polishing when a brush of wire or bristles are used as the work performing rotor.
Also as the driving shaft means is flexible, and vibration of the engine is not conveyed to the outside of the fitting frame; when the internal combustion engine, remain fixed within the fitting frame, is taken down on the ground and the discoid cutter is fixed perpendicularly on the worktable like an ordinary bandsaw, the disclosed structure can be used as a sawing machine. Also when the screw propeller of a boat is inserted, instead of the work performing cutter tool A, and lowered from the stern of the boat into the water, it can be used as a propeller for boat propulsion.
As mentioned above, the device of this invention is a portable machine which is used on the operators back. It is light in weight and quite unparalleled when compared to other kinds of manufactures. This suggests that, as mentioned above, the driving shaft itself is beneficially constructed to be of light weight and that, as no loss is caused by friction as with gear wheels, the power of the engine E is communicated most efficiently to the tool A. Even an engine E of small size and power has, in operations like felling trees, a greater capacity for work than other manufactures hitherto in use have exhibited, and thus the light engine E of ample power.
As the discoid cutter can be turned to any direction at will, the edge of the cutter can be applied vertically to any wood to be cut, which greatly contributes to the excellency of this invention, particularly in the tree felling area. To cite data, a moving machine hitherto in use, when provided with an engine of 50 cc. cylinder displacement per stroke can cut wood of 5 to 6 cm. in diameter as a maximum, while that of this invention, when it is provided with an engine of 35 cc. displacement, can cut wood of 35 to 40 cm. in diameter.
As the tool A can be turned to any direction at will while it is operating, in mowing weeds or in cutting away of bushes, the operator, with the device of this invention,
can mow or cut away at any place, whether it is a hilly place or the bottom of a ravine with uneven slopes no matter how sharp, or a tortuous foot path between rows of crops such as rice.
In lopping branches in a forest, no matter what direction branches spread, the rotating edge of the cutter can be applied to them perpendicularly. Furthermore, the machine is of light weight and little fatigue is experienced by vibration so that the operator, with the machine of this invention, can continue to work efliciently for a long time at a stretch.
What I claim is:
1. A work performing tool for universal movement of the tool in three dimensions by an operatior comprising a flexible shaft including a flexible tubing surrounding a flexible core, means to supply power to one end of said flexible core, means to mount a working tool with a housing on the other end of said flexible shaft with the tool connected to said flexible core while preventing the housing of said tool from moving relative to the said other end of said flexible tubing, a first rigid tubing surrounding said flexible tubing and said flexible core and spaced from both ends of the flexible shaft preventing bending of said flexible shaft within said first rigid tubing, a second and shorter rigid tubing mounted on said first rigid tubing for longitudinal and rotational movement relative to said first rigid tubing, a connecting rod connecting said second rigid tubing to the casing of said tool whereby said tool can be manipulated by said first and second rigid tubing to move in three dimensions for performing work in any plane at any angle.
2. The invention according to claim 1 in which handles are provided for manipulating each rigid tube in axial, angular, and rectilinear movement and any combination thereof whereby the working tool can be moved in all directions.
3. A work performing tool for universal movement of the tool in three dimensions by an operator comprising a housed power conveying shaft including flexible shaft sections, each having a flexible tubing section surrounding a flexible core, means to supply power to one end of one flexible core in one flexible shaft section, means to mount a working tool with a housing on the outer end of the other flexible shaft with the tool connected to the flexible core of said other flexible shaft section while preventing the housing of said tool from moving relative to the other end of said other flexible tubing section, a first rigid tubing extending between said flexible tubing sections and said flexible core and spaced from both outer ends of the flexible shaft tubing sections and secured to said flexible tubing sections against longitudinal and rotative movement preventing bending of said core within said first rigid tubing, a second and shorter rigid tubing mounted on said first rigid tubing for longitudinal and rotational movement relative to said first rigid tubing, a connecting rod connecting said second rigid tubing to the housing of the said tool whereby said tool can be manipulated by said first and second rigid tubings to move in three dimensions for performing Work in any plane at any angle.
4. Apparatus to be carried on a persons back compris ing a first frame, means to secure said first frame to a persons back, a second frame pivotally mounted on said first frame for rocking movement about a vertical axis, a motor on said second frame, a flexible shaft including a flexible core extending transversely from said second frame and transversely to said vertical axis and drivingly connected to said motor and a flexible tubing snugly surrounding said flexible core and connected to said second frame and serving as the bearing for said flexible core with a minimum of clearance to avoid whipping of said flexible core in said flexible tubing, manipulating mean intermediate the ends of said flexible shaft, means to substantially stiffen the flexible shaft from the motor to a point adjacent the manipulating means, means to support a tool on the free end of the flexible shaft, the free end portion of said flexible shaft between said manipulating means and said means to support a tool being relatively more flexible than the stiffened flexible shaft between said motor and said manipulating means whereby the tool may be adjusted to any angle in any direction.
References Cited by the Examiner UNITED STATES PATENTS 434,748 8/1890 Almond 642 1,520,330 12/1924 Chinn 14343 1,981,076 11/1934 Sells 224--5.3 1,993,368 4/1935 Goldberg 644 2,519,936 8/1950 Sayer 14343.8 2,563,195 8/1951 Soule et a1 143-438 2,564,019 8/1951 Martin 64--4 2,598,565 5/1952 Lagant 173--163 2,655,957 10/1953 Lagant 14343 2,697,457 12/1954 Lawrence 173170 2,792,670 5/1957 Haynes 14343.8 2,909,068 10/1959 Hang 74-16 BROUGHTON G. DURHAM, Primary Examiner.