US2725753A - Portable power operated tool - Google Patents

Description

Dec. 6, 1955 R. J. HAUG PORTABLE POWER OPERATED TOOL 2 Sheets-Sheet 1 Filed July 18, 1951 Fi 5A INVENTOR. RICHARD J. HAUG BY Dec. 6, 1955 R. J. HAUG PORTABLE POWER OPERATED TOOL Filed July 18, 1951 2 Sheets-Sheet 2 'IIIIIIIIIII" A 1.93 INVENTOR.

RICHARD J MUG BY Fi ll 97 199 *7: 9' 198v W 4 United States Patent Office 2,725,753 Fatented Dec. 6, 1955 PORTABLE POWER OPERATED TOOL Richard J. Hang, Nashua, N. H. Application July 18, 1951, Serial No. 237,462 13 Claims. (Cl. 74-16) This invent-ion relates to portable tools of the type in which a light internal combustion engine is suspended from the backof the :user andatool is powered therefrom by a-movable power-transmitting member. My invention is especially adaptable and useful for powering a rotary cutting tool, such ,as a circular saw, when used to remove brusha-nd small trees or forrsimilar purposes.

' The principal object of my invention is to connect such .a tool with the engine by asingle, lightweight, elongated handle made up of rigid-, jointed casings which also serve as guides for operating the tool. Another object of my invention is to transmit power through said casings by means of V belts and pulleys rather than by rigid shafts or flexible shafts and thereby to achieve a reduction in .cost' of manufacture, an ease of replacement in. remote brush. covered areas and an unusually light Weight at the tool head and in the power transmitting member.

Still another .object .ofmy invention is to articulate m-y rigid power-transmitting handle by providing a short rigid housing, verticallypivoted to .the engine and extending .under one armof the .user to.a knee joint, .01 hinge joint,

lllwflIOllt of one side .of said .user, by mounting a horizontally-pivoted, longer, rigid housing on the. knee joint which extends ,over beyond the other side of the user and by mounting the tool head .for rotation around the free end of said longer housing. The rigid jointed housings thus are in a position .to be grasped by both hands of the user, .the tool can be raised or lowered with case on the side of the user, opposite to said shorter arm, and: if the user stumbles and. falls the lengthand rigidity .of the housings preventhis falling onthetool.

A further object of my invention is the. provision of an improved vibrationless mounting ,for the engine on the back of the .user and .a novel eccentrically pivoted closure for the tool head which permits easy access when it is necessary to substitute a newbelt. A still further object of my invention is the provision of .a separable knee joint, intermediate of the rigid. housings, whereby the longer housing .can be detached when the device is .being moved in an automobile, and the provision of a novel clutching and braking. means, preferably associated with said knee joint.

I am aware that previous tools of this. nature haveused flexible shafts to transmit .power, have had .a rigid sleevelike housing around a, rigid powershaft and .that separate rigid handles have been provided to serve as a guide, or operating control. .I have found, howeventhat light flexible shafts tend. to break downunder :a full .day of use, such .as in .brush cutting, and stronger flexible shafts, or rigid shafts and ,gears tend -to-such weight that they quickly tire theuser. 1 have also found that separate rigid handles and independent: flexible .shaftsform a fork in which brush will .catchand {become lodged and also quickly tire the .user. Withmy rigid jointed housings, .and belt and pulley power transmission, the weight of the shorter housing. is transferred to -the. .backof the user, .the longer housing is light and easily maneuverable into difiicult places 2 and one hand of the user can be removed therefrom while still retaining full control by the other hand.

In the drawings,

Fig. -1 is a side elevation of my invention on the back of a user.

Fig. 2 is a plan view of my invention removed from the back of the user. 1

Fig. 3 is an enlarged front view of the elongated housing of my devicedetached from the device.

Fig. 4' is a plan view of the elongated housing shown in Fig. 3.

Fig. 5 is an enlarged front view of'the shorter :housing of my device.

Fig. 5A is a view similar to Fig. 5-of a modification.

Fig. 6 is a plan view of the shorter housing shown in Fig. 5.

Fig. 7 is an enlarged, fragmentary side view, in section of the separable knee joint and brake and clutch means of my device.

Fig. 8 is an enlarged plan view on line 8-8 of Fig. 7 illustrating the brake and clutch means.

Fig. 9 is an enlarged, fragmentary side elevation in section, of one of my new anti-vibration members for supporting the engine of my device.

Fig. '10 is an enlarged, fragmentary plan view in sec- -ti'on showing the connection of the shorter housing to the .engineand Fig; 11 is an enlarged fragmentary side View in section of the eccentrically pivoted closure for the toolhead of my device.

As shown in Figs. 1 and 2, the portable internal combustion engine A, of my device, is of a well known type. it is mounted on an anti vibration means B, provided with suitable straps 20 whereby it can be easily supported on, or removed from, the back of a user M. The drive shaft 21 of engine A is preferably about opposite the waist 22 of the user M, and extends over to a point approximately in rear of the left elbow joint 23 of the user. The engine A is usually started by a rope or otherwise, before the device is placed on the users back and'its speed may be controlled by a convenient flexible connection 24 to the engine-throttle.

' The tool G of my device, such as the circular saw illustrated, is freely movable at the end of what I call an articulated, power-transmitting tool handle member shown at C, D, E and F in Fig. 2, the member preferably having a grip-Hfor the right hand of the user M.

The first, or connecting section C of my articulated member, is a rigid, tubular housing, preferably of circular cross section and formed of a light weight metal. Housing C could obviously be formed of a one piece hollow tube, if desired, but for ease of manufacture and ease of varying the length thereof, I prefer to form the same with what I call a swing-head and a knee joint head '51 of cast metal, separated by a metal tube 52 of the desired length.

Swing head 50 includes a recess 53 in which the adjacent end 54 of tube 52 is held, as shown in Fig. 10, and is provided with a recess 55 at its other end which is journalled on a fixed horizontal pivot 56' onengine A. Pivot 56 is located several inches behind the left elbow joint 23 of the user thus permitting the housing C to oscillate in a vertical plane around the left side of the user and, when extending forwardly of the user, positioning the tube 52 of housing C between the left arm and the body ofthe user. The drive shaft 21 of engine A is journailed at the centre of horizontal pivot 56 and extends to a driving pulley 25 fixed on the shaft at the longitudinalwcentre line of swing head 50. It will be obvious that driving pulley 25 :thus remains in the same relative position in housing C regardless of tion in a vertical plane thereof.

the position of .oscilla Knee joint head 51, of housing C, includes a recess 60 in which the adjacent end 57 of tube 52 is held, a shoulder 61, a cut away portion 62, and a flattened extension 58 provided with a pulley recess 59. As shown in Fig. 7, knee joint D contains a double pulley 70, with one half of said pulley 71 revoluble in recess 59 of the extension 58 of knee joint head 51 and the other half 72 of the pulley 70 rvoluble in a similar recess 91 in the flattened extension 93 of the knee joint head 90 of housing E.

Knee joint head 90 of housing E is provided with an enlarged portion 92, from which projects the flattened extension'93, similar to 58. 90 also includes an internal shoulder at 97, a cut away portion 98 and a portion 94 ofgreater internal diameter than at 92 in which tube 95 of housing E is slidably and revolubly retained. An annular sleeve 96 is provided proximate the end of tube 95 and a coil spring 99 encircles tube 95 between sleeve 96 and the end 950 of head 90. Sleeve 96 is of the split type and may be tightened into position on tube 95 by a bolt and nut shown at 953. One end 954 of spring 99 is inserted in the split of sleeve 96 and the opposite end 955 is inserted in a cut out 956 in sleeve 96. Coil spring 99 urges the pulleys 130 and 72, located at opposite ends of housing E, away from each other, thus maintaining constant tension on the belt 2 connecting the pulleys.

I prefer to use an engine A, of the type having a horizontal drive shaft 21, whereby double pulley 70 revolves in a plane at right angles to the plane of driving pulley 25. Half pulley 71, of pulley 70, is operatively connected by afiexible quarter twist belt 104 to driving pulley 25, the belt 104 being contained within tube 52 of housing C. Half pulley 71 is journalled on a sleeve 105, by suitable bearings 106 and the sleeve is fixed in a hole 107 in the centre of extension 58 of knee joint head 51., Similarly half pulley,72 is operatively connected by a flexible belt 121 toa driven pulley 130 in the tool head F, the belt 121 being contained in the tube 95, of housing E. 72 is journalled on a sleeve 108, identical with and aligned with sleeve 105, there being suitable bearings at 109 and a hole 110 through the centre of extension 93 of knee joint head 90 of housing E in which sleeve 108 is fixed. The contacting ends of sleeves 108 and 105 are flush with the adjacent . diametrical surfaces 111 and 112 of their respective half pulleys 72 and 71 and driving pins 113 and 114 projectfrom one of said diametrical surfaces such as 111 into registering driving pin holes 115 and 116 in the opposite diametrical surface such as 112. Spring rings, 117 and 118 of a well known type-are also provided to retain the half pulleys on their respective sleeves when the knee joint is separated.

A headed bolt 150, having a nut 151, retained by a leaf spring 152, passes through the central openings 154 and 155 of sleeves 105 and 108 to detachably retain knee joint head of .E on knee joint head 51 of C. It will be apparent that knee joint D permits housing E to oscillate horizontally on a vertical pivot formed by sleeves and 108 and bolt 150. Also that when the knee joint D is assembled in operating position, half pulley 71 which is rotated by belt 104 from driving pulley 25, will through driving pins 113 and 114, in turn rotate half pulley 72 and the latter, through belt 121, will rotate driven pulley in tool head B.

When the device is not in use, leaf spring 152 may be flexed, nut 151 unthreaded from bolt and knee joint head 58 with its sleeve 105 and half pulley 71 may be slid off bolt 150 to detach the elongated housing E from housing C. 7

Tool head F, like the other parts of my new articulated tool handle, is preferably of light Weight metal and may be a casting having a recess in which tube 95 is fixed as shown in Fig. 11. The front and side walls of tool head F are cut away on horizontal line 190 and vertical line 191 and are replaced by a curved metal plate 192, removably secured to the tool head F by bolts 193.

The upper wall 178 of tool head F is cut away to form 193 and bolts 4 a curved edge 179 and includes a flat shelf portion 194, provided with threaded bolt holes 182, and a curved vertical shoulder 180.

A driven pulley 130 is mounted on shaft 172, the shaft 172 being journalled in suitable lower bearings 173 in a bearing recess 195 intermediate of lower wall 196 of tool head F. A tool G, such as a circular saw, is fixed to the outer threaded end of shaft 172 by a nut 197 and collar 198, the collar having a packing ring 199, and an upturned flange 900 arranged to prevent fouling of the shaft with leaves or grass.

I provide an eccentrically swivelled cover 175, as an upper closure for tool head F, cover 175 having a hearing recess 901 for the upper bearings 902 of shaft 172 and a recess 903 for an upper nut 904, the nut 904 being threaded on the upper end of shaft 172. A cover 905 is removably secured by bolts 906 over recess 903. Swivel cover 175 is thus rotatably mounted on shaft 172 and can be swivelled in an arc of to the position shown in dotted lines.

Swivel cover 175 has one curved peripheral edge 184 at a less distance from shaft 172 than its opposite curved peripheral edge 185, edge 184 fitting within plate 192 and edge 185 conforming to and abutting on the curved edge 179 of wall 178. A flange 186 projects upwardly from edge 185 and thence outwardly at 187 to overlie portion 194 of wall 178, unthreaded bolt holes 907 being provided in 187 to register with bolt holes 182 of portion 194. p

In the event that a belt such as 121 requires replacement, plate 192 is removed by unthreading bolts 908 are unthreaded from holes 182 in wall 178. Cover 175 may then be swivelled on shaft 172 to the dotted line position leaving a space 910 between edge 184 and cage 179. A new belt, such as 121, is then passed through tube 95 so that its end loop projects out of space 910, thus permitting cover 175 to be refastened by bolts 908 and the end loop of the belt to pass over the cover and onto pulley 130. Plate 192 is then replaced and the substitution of belts complete.

, Since tube 95 is preferably fixed at one end to tool head F and is slidably and revolubly mounted at its other end in the portion 94 of knee joint D, the user can rotate tool head F around the longitudinal axis of housing E by means of grip H and thus change the angle of the tool G.

I provide a novel clutch and brake means as shown in Figs. 7 and 8 which preferably is associated with one of the half pulleys of knee joint D such as 72 for convenience of access, although it could obviously be associated with pulley 25. As shown a groove 201, with perpendicular side walls, is formed at the base of the V groove in a half pulley, such as 72 of knee joint head 90 of housing E. A U-shaped strip of spring steel 202 is retained within the groove but is of suitable cross section to prevent its bearing on the bottom or sides of the groove 201 or the inner surface of the flexible V belt 121 with undesirable friction. The ends of strip 202 are retained in a transverse rigid retaining element 203, positioned to advance and retract within recess 91 of extension 93 of 90. Element 203 is fixed to a rod 204, passing through a hole 205 in therwall 206 of 91 and into the interior of the enlarged portion 92 of knee joint head 90. A bell crank lever 260, hinged at 207 on a pin 208 has its shorter section 209 in contact with the free end of rod'204 and its longer section extending outside of 92 to form a hand control lever 210.

I provide a plurality of rollers 950 in the V-shaped strip 202 arranged to provide rolling contact with the inner surface of belt 121 and thereby to prevent stalling of the engine A during the initial contact of the strip with the 'belt.

When lever 210 is pressed inward, rod 204 and eleenaagrsn ment 203-ad vance the resilient strip. 202 out of groove 2&1 and carry rollers 950 into contact with the inner surface of belt 121- thus separating the belt from the pulley. Upon further pressure of lever 210 the strip 202 completely d-isengages the belt 121 from "the pulley 7-2 and forces it against the. walls of the recess 91 thus stopping the movement of the belt entirely and permitting the pulley tocontinue revolving. The coil spring 99-, which keeps the belt 121 taut within casing E by continually pressing on sleeve 96, returns the belt to its normal position on the pulley 72 when pressure on lever 2P0 is released andthebelt forces the parts of the clutch and brake device back to theirnormal positions.

As shown in Fig. 9, my anti vibration means-B includes an engineplate 3300- uponwhich engine A is rigidly' mounted. -It also includes a back plate 301 to which the straps 20 are attached. To support engine A, without vibration transmitted to the user M, and with a heat insulation space "between engine and user anti-vibration spacers P are provided,between the plates 300 and 301. I attach an inverted cup 303 to the back plate by rivets orbolts 304 the cup having a central opening 311 and'the back plate having a similar opening 305. A carriage bolt 306 -is attached to the engine plate 300 by a nut 307 and passes through a spacer 308 into a soft rubber insert 309 retained in place by cup 303. The bolt head 3&0 is accommodated by the opening 305in-back plate 301 and-it will be apparent that the metal engine plate 300 and the bolt 306 do not contact the back plate 301 but are connected thereto only by the soft rubber insert 309-which absorbs enginevibration at the same time that it supports the engine A on the users back. An air space 312 is also provided between engine plate300 and back plate 3'01 to insulate the user M against the heat of the engine A. I In operation, it is first necessary to attach housing-E to .housingC if ithas been detached for carrying; The knee joint head 51 of housing C is placed orr'knee joint head'a9ll of housing E so-that pins '113 and 114 enter holes 1135 and 1116 and sleeve 105 slides onto bolt 150 until flush with the end of sleeve 1%. The nut 151 is then placed on bolt 150 to complete the assembly of knee joint '1). The engine A may then be started, and placed on the users back, being separated therefrom by' my anti-vibration means B. The housing C passes under the left arm of the user to bring the knee joint D in front and to the left of the user in convenient reach of the left hand .of the user. Housing E extends over to the from right side of the user, with grip H in convenient reach of the right hand of ,the :user. The .users ileft hand also encircles hand lever 21 and presses upon the same to detach the belt 121 from pulley 72 untilit is desired that the tool .6. revolve. The throttle may be controlled by the rightv hand of the user by means of flexible connection .24. The tool G can be raised or lowered ion the swing-head, 5.0 as .a pivot or moved forward and backward on the knee joint D- as a pivot while in any position the .tool head. is, rotatable about, housing E". do addition, by the user. leaning forward or backward, even greater movability of tool G is achieved.

As shown, housing C is not rotatable on its longitudinal axis although such rotation could be secured by constructing it in the manner of housing E as indicated in Fig. 5A. I prefer the construction shown in Figs. 5 and 6 because I find the tool G is freely movable and easily guided when only the housing C is capable of revolving on its longitudinal axis. In Fig. 5A a coil spring 960 similar to 99 and a flanged tube 961, similar to 95, are substituted for the tube 52 thus providing automatic tensioning of the belt and rotation on the longitudinal axis similar to housing E. Since belt 121 is not twisted in its normal position, it can be twisted by the rotation 10 of tool head F at least through a quarter twist in either direction if desired without affecting the transmission of power.

I may provide an arcuate elongated slot 970 in tube *95, and an upstanding pin 971 on tube 94 of housing E, the pin being movable only to the Ii'mits'of the slot and thus preventing the rotation of tool head-F to-the point of crossing of the belt 121. I may also provide a coil spring 980 between the straps 20 and the housing E, as shown in Fig. 2, to counterbalance the weight of housing E, tool head F and tool .G. It is obvious that my device can be adapted for -use by a left handed person mounting the engine A, to bring the drive shaft 21 over to the right side of the user, whereby housing C will pass under the right arm and hand gripH be positioned for the left hand of 'theuser.

Obviously the clutch control handle 260 can be arranged by suitable springs so that the clutch is normally disengaged and is engaged only-whenthe operatorpresses the handle 260.

It is also obvious that I could provide ashort belt connection between thepowerpulley 25'and a-pulley mounted on the engine shaft 21 to facilitate substitution of various sizes of pulley thereby securinga variety of-power ratios. i I claim: a

-l. A power operated portable tool comprising an internal combustion engine; means for supporting said engine on the back of a user; a short, rigid hollow mechanical power-transmitting housing, pivoted to said engine for oscillatory movement in afirst single plane, and extending forwardly under an arm of said user to a point in front thereof; an. elongated, rigid hollow mechanica'l power-transmitting housing, pivoted at the free end-o'fsaidshort arm for oscillatory movement-inn second single, plane substantially at'rightangles to said first plane and-extending to -a tool head and said tool head, ineluding a- -tool, rotatably mOunted at the end of said elongated housing, to turn around the longitudinal axis of said housing.

2. A power operated tool, comprising an internal cornbastion-engine; means for-supporting said engine on the back of a user; a hinge jointed, tubular handle extending forwardly from, andhaving one end pivota'lly supported by said engine, arotary tool mounted 'to rotate around the opposite end of said 'handle and belt and pulley" power transmission mechanism substantially wholly contained within said handle for operatively connecting said engine with said too Apower operated tool, comprising an internal combustion engine; means for supporting said engine on the back of a user; a hinge jointed handle formed of a pair of rigid, tubular housings extending forwardly from, and having one end supported by said engine, a rotary tool mounted to rotate around the opposite end of said handle; belt and pulley power transmission mechanism substantiallywholly contained within said handle for operatively connecting; said" engine with said tool and power disconnecting and connecting clutch means, 10-

cated withinone of said housings and operable from outside the same for removing abelt from, and returning saidbelt "into, engagement with a pulley of said power transmission mechanism.

4. A power operated portable tool comprising an internal combustion engine; means for supporting said engine on the back of a user; a short, rigid tubular housing pivoted to said engine for vertical oscillatory movement and extending forwardly to a knee joint in front of a side of said user; an elongated, rigid tubular housing pivoted at said knee joint for horizontal oscillatory movement and extending to a tool head; said tool head, including a tool, rotatably mounted at the end of said elongated housing; and mechanical power transmitting means within said tubular housings comprising a driving pulley powered by said engine and axially aligned with the horizontal pivot of said short housing; a driven pulley in the tool head, operatively connected to the tool; a double pulley in the knee joint, at right angles to said driving pulley; a flexible belt connecting the driving pulley with one half of said double pulley and a flexible belt connecting the other half of said double pulley with said driven pulley. Y

5. The machine described in claim 4 plus quick release means for disengaging said housings at the knee joint, said means including inter-engaging elements on each half of said double pulley.

. 6. The machine described in claim 4 plus an eccentrically swivelled cover on said tool head adapted to form a belt opening when in open position.

7. The machine described in claim 4 plus clutch and brake means, associated with one'of said pulleys and adapted to contact and move a driving belt out of contact with the belt groove in said pulley and into contact with the inner walls of the pulley recess.

8. The machine described in claim 4 plus anti-vibration means between said engine and theusers back, said means. comprising a back plate provided with inverted cups, each having a central bolt opening therethrough; an engine plate having projecting headed bolts each extending into one of said cups through said opening and each having a spacing sleeve therearound and a soft rubber insert, encircling each bolt between the head and an end of the spacer sleeve, and wholly retained and supported within said inverted cup.

9. A mechanical power transmittinghandle comprising a short, rigid tubular housing and an elongated rigid tubular housing connected together by the pivot pin of a knee joint; a double pulley mounted on the pivot pin of said knee joint; a driving pulley at right angles to said double pulley and located at the opposite end of said short housing; a quarter-twist belt connecting said driving pulley with one half of said double pulley; a driven pulley mounted to rotate around the opposite end of said elongated housing and a flexible belt connecting said driven pulley with the other half of said double pulley.

10. A mechanical power transmitting handle comprising a short, rigid tubular housing and an elongated, rigid tubular housing; a knee joint including a pivot pin, connecting the adjacent ends of said housings; a double pulley mounted on the pivot pin of said knee joint; a driving pulley at right angles to said double pulley and located at the opposite end of said short housing; a quarter-twist belt operatively connecting said driving pulley with one half of said double pulley; a driven pulley mounted to rotate around the opposite end of said elongated housing; a flexible belt operatively connecting said driven pulley with the other half of said double pulley and means for quickly engaging and disengaging the adjacent ends of said housings at said knee joint.

, 11. In a portable power operated tool, adapted to be bodily transported and used by a single individual, the combination of a gasoline engine having a drive shaft with a pulley at the terminal end thereoffor powering said tool; an elongated hollow tubular member, of rigid material, said member having one end pivoted to said engine to rotate in a single plane around the central longitudinal axis of the drive shaft and pulley; an elongated a driven pulley at the said sleeve,

hollow sleeve of rigid material having hand gripmeans thereon'and mounted to rotate around the central longitudinal axis of said member adjacent the free end thereof; a tool head having a tool on the exterior thereof and a-pulley, operably connected to said tool, in the interior thereof, said tool head beingfixed at the terminal end of and a flexiblebelt trained around said drive shaft pulley and said tool head pulley and substantially entirely enclosed within said toolhead, sleeve and tubular member.

12. A mechanical power transmitting handle, for use in guiding and driving a cutting tool at a distance from a portable engine, said handle comprising an elongated, hollow, tubular body of self supporting rigid material; a pair of heads, each fixed at an opposite end of said body but angularly disposed around the central longitudinal axis of said shaft at an angle of'90 from each other; a pair of pulley shafts, each journalled in one of said heads and extending normal to said body axis but angularly disposed therearound at an angle of from each other, a pair of pulleys each'revolvable with one of said shafts and each positioned opposite an opposite endof said tubular body and a flexible belt trained around said pair of pulleys and quarter twisted intermediate thereof for transmitting power from one said head to the other while substantially enclosed and protected by said body member.

13. ,A mechanical power transmitting handle for use in guiding and driving a cutting tool at a distance from a portable engine, said handle comprising an elongated hollow tubular body of self supporting rigid material; a drive head mounted at one end of said body and including a pulley drive shaft normal to the longitudinal axis of said bodyand a drive pulley at the terminal end of said shaft opposite the end of said body; a tool head mounted at the other end of said body and including a pulley driven shaft normal to the longitudinal axis of said body and terminal end of said driven shaft opposite said other end of said body; a pivot connection between said tool head and said body for enabling the turning of said head angularly around the central longitudinal axis of said body and a flexible belt, trained around said drive pulley and said driven pulley and substantially entirely enclosed within said body for transinitting power between said pulleys and inside said handle.

References Cited in the' file of this patent UNITED STATES PATENTS

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