US3049841A - Portable sanders - Google Patents

Description

Filed July 15, 1959 3 Sheets-Sheet 1 I s I I I 3 20 g M IIIHHH" H 5E H N Milt! y X2 I m m. A,

' INVENTOR.

Y J. EDWIN GUINN %//Wz%},4;

ATTORNEY Aug. 21, 1962 J. E. GUlNN 3,049,841

PORTABLE SANDERS Filed July 13, 1959 s Sheets-Sheet 2 INVENTOR. J. EDWIN GUINN BY Z; (an FIG. 4 J/MW ATTORNEY Aug. 1962 J. E. GUINN 3,049,841

PORTABLE SANDERS Filed July 13, 1959 I5 Sheets-Sheet 3 J. EDWIN GUINN FIG.8 ;wz M

ATTORNEY 3,049,841 PQRTABLE SANDERS J. Edwin Guinn, Riviera Beach, Fla, assignor of onefourth to Amos E. Jackson, Palm Beach, Fla, and one-fourth to H. E. Knight, Riviera Beach, Fla.

Filed July 13, 1959, Ser. No. 826,793 4 Claims. (til. 5117tl) This invent-ion relates to sanders, and more particularly is directed towards hand sanders of the belt type having the motor inside the frame and loop of the belt.

An object of this invention is to provide a power driven abrasive belt device suitable for arcuate and flat surface sanding.

Another object of this invention is to provide a device of the class described with a driven pulley encasing the motor and connected therewith through a new arrangement meshing reduction gems.

Another of this invention is to provide a device of the class described with new and improved frame supporting all operable parts and having a minimum of weight.

Another object of this invention is to provide a device of the class described with take-up roller mechanism to maintain tracking tension on the abrasive belt.

Another object of this invention is to provide a handle for a device of the class described which will eliminate or minimize the effect torque of the motor.

Another object of this invention is to provide a portable power driven abrasive belt device suitable for abrading or cutting concave and convex curved surfaces in nonferrous metal and some ferrous metal, wood, plastic and the like.

Another object of this invention is to provide a portable power driven abrasive belt device suitable for smoothing and finishing concave and convex curved surfaces of any material affected by abrasives.

Another object of this invention is to provide a port able power driven abrasive belt device suitable for cutting or finishing concave multiple curve surfaces.

Another object of this invention is to provide a portable power driven abrasive belt device containing all the features described herein including any power source.

A further object of this invention is to provide a device of the class described which will be simple and eco nomical in construction, and light in weight, efficient and durable in use.

This invention is an improvement in my Patent Number 2,560,102, issued July 10, 1951.

The foregoing and other objects and advantages of this invention will be more apparent from the following specification, in conjunction with the drawing forming a part thereof, wherein:

FIG. 1 is a side elevation view of the sander, with broken lines showing a curved surface work and the position of the belt when operating on such work;

FIG. 2 is a sectional view taken in line 22- of FIG. 1, parts shown in elevation for clarity;

FIG. 3 is a sectional view taken on line 33 of FIG. 2;

FIG. 4 is a sectional view taken on line 44 of FIG. 3.

FIG. 5 is an end elevation of the device of this invention showing one of a pair of adjustable handles positioned on the axis of the motors and the center of gravity of said device;

FIG. 6 is a plan view of the device of FIG. 5;

FIG. 7 is a sectional view taken on line 77 of FIG. 5, parts shown in elevation for clarity; and,

FIG. 8 is a sectional view taken on line 8-3 of FIG. 5, with handle released position shown in dotted outline.

Referring to the drawings, wherein like members are c' lg given the same reference numeral, a pair of substantially Y-shaped members 1 and It comprise a basic frame having a driven belt pulley 2 pivotally mounted for free rotation intermediate the planes of said frame members 1 and 1', which are spaced apart by drum housing 3 incasing a motor which tunis a shaft mounted gear 4 meshing with an idler reduction gear 4 to rotate the pulley 2 through internal gears 5 meshing with the idler gear 4'.

Idler aligning pulley 6 and 6' are pivotally mounted parallel to the driven pulley 2 by pivot pin 7 and 7', respectively positioned in one leg of the Y-shaped frame member 1 and '1', with one of the pulleys 6' being positioned at the terminal or free end of said leg, a gate leg 10 is pivotally connected to the free end of the other leg of the Y-shaped frame member 1 and 1'.

The gate leg 10 is capable of yielding inwardly against the action of a spring 8 when the sander is pressed against an arcuate surface, as shown in FIG. 1; and, the outer limit of the gate leg 10 position can be readily adjusted by the nut 11 or the bolt 12 which is pivoted to the frame members '1 and 1. Suitable lock nut or stop nut 13 is provided in conjunction with the nut 11.

A pivot pin 15 journals an idler pulley 16 between frame members 1 and 1 and also ends of the gate legs it? with spacer bearings 17 positioned in each end of the pulley 16. The iree end of the gate legs 10 have journaled therebetween a similar pulley 16 with spacer bearings 17 in the ends thereof receiving a pivot pin -15. The pulley 16' is adjustable with respect to longitudinal axis of the gate leg 10, by means of a rotatable member 13 receiving pivot pin 15 eccentrically, and a releasable lock nut 19.

The idler pulley 6 and 6' are positioned to have a common tangential plane with driven pulley 2; and, the tension of spring 8 is adjusted to position idler pulleys l6 and 16' in a common tangential plane with driven pulley 2 when no force is exerted on the sander belt Ztl.

A flat press-plate is secured to the fixed legs of the frame members and 1' intermediate the pulleys 6 and 6' and beneath the plane of the belt 20 for flat surface sanding.

For heavy sanders, and preferably for smaller sanders also, the frame has a normally horizontal opposed legs 23, 23' to which the gate legs are pivoted, and a pair of vertical legs 24, 24 having a plurality of radially spaced recesses therein to receive projections 26 on a handle 27 secured to said legs 24, 24 by threads 28 on a thumb bolt 29 received by a tapped aperture 30 in said legs.

The handles 27 are machine-gun grip type with the projections 26 diametrically opposed to be received by diametrically opposed recesses 25. The recesses 25 on one of the leg 24 are aligned with the recesses on the opposed leg 24, so that with the projections 26 in a pair of aligned recesses 25 in the leg 24 and 24' the bandles 27 are aligned and parallel.

This handles 27 are releasably secured to the legs 24, 24', by the thumb bolt 29, in the axis of the motor, which is the axis of the center of gravity of the device.

By releasing the thumb bolts 29, the handles 27 can be rotated to any desired common position and be in alignment for Work in any position.

For lightweight sander, a single handle may be used in which an L-shaped handle 21 has the end of one leg thereof secured to the frame member 1 along the longitudinal axis of the motor and driven pulley 2, with the leg thereof extending transversely across belt 20 and spaced from the pivot point of the gate leg 10. A protector plate 14 is positioned intermediate the belt 20 and free leg of the handle 21 by fastening to the frame member 1.

To assure aligned tracking, the pulleys have a center crown of approximately three degrees.

In operation the device is quite simple and light in weight. With the motor actuated, the shaft gear 4 rotates the reduction idler gear 4', which rotates the driven pulley 2 by meshing with the internal gears 5. The sanding belt 20 is unrestrictedly rotated by the driven pulley 5 end and the idler pulleys 6, 6, 16 and 16'. By pressing the device on flat work with the presser plate 22, flat sanding is accomplished; and, for arcuate sanding the device is pressed against the arcuate surface positioned intermediate the free end 6 of the gate leg and free end of the leg of frame member 1, the spring 8 yielding to permit the gate leg 10 the pivot inwardly to provide wrap around surface of the sanding belt 20 for the arcuate surface of the work.

For concave cutting or sanding the device is held in a vertical position and pressed into the work piece or against the concave or multiple curve surface positioned intermediate the free end 6 of gate leg 10 and free end of the leg of frame member 1, the spring 8 yielding to permit the gate leg 10 to pivot inward to provide for belt 20 to flex in the direction of the concave or multiple concave curves or surfaces of the work.

The sander belt 20 frequently wear or stretch in use. When such occurs, the thumb nut 19 is turned to free the eccentric member 18, which is rotated to extend the roller 16' outwardly to tighten the belt 20, and the nut 19 is then retightened to lock the eccentric member in position.

The L-shaped handle 21 having the manual force transversely exerted counter-clockwise and transmitted to the longitudinal axis of the motor counteracts the inherent motor torque to assure smooth and accurate control of the sanding operations with small embodiments of this device.

While the invention has been described ina certain specific form by way of illustration, the invention is not so limited, as modifications and changes can readily be made therein without departing from the spirit and scope thereof as defined in the appended claims.

What is claimed as new and desired to secure by grant of Letters Patent is:

1. In a portable hand sander, the combination of a pair of spaced substantially Y-shaped frame members, power means mounted between said frame members, a driven pulley pivotally mounted between Said frame members and surrounding said power means, gear reduction means connecting said power means and said driven pulley, gate legs pivotally mounted to the free end of opposed legs of said Y-shaped frame members, adjustable resilient means connecting said gate legs and frame members, a plurality of idler pulleys journaled in said frame members and gate legs parallel to said driven pulley and having common tangential planes with said driven pulley, a continuous sanding belt positioned around said pulleys, a presser plate fastened to said frame members and positioned intermediate said frame members and said sanding belt, adjustable means for displacing the longitudinal axis of at least one of said idler pulleys, and handles secured to said frame members along the longitudinal axis of said power means.

2. In a portable hand sander, the combination of spaced frame members, a driven pulley pivotally mounted between said frame members, means positioned interior of said driven pulley and supported by said spaced frame members for driving said pulley, legs pivotally mounted to said frame members, adjustable resilient means limiting the position of said pivotal legs in one direction and permitting said legs to pivot in the other direction against the action of said resilient means, a plurality of idler pulleys journaled in said frame members and pivotable legs parallel to said driven pulley, a sanding belt loop slidably positioned around said pulleys, means for adjusting the axis of rotation of at least one of said pulleys, a presser plate fastened to said frame members and positioned intermediate said frame members and said sanding belt loop, and an L-shaped handle having one leg thereon secured to one of said frame members along the longitudinal axis of 7 said driven pulley and the other leg of said handle positioned transversely of said sanding belt and spaced from said pivotal leg to exert pressure in a direction opposite the movement of the sanding belt when in use.

3. In a portable hand sander, the combination of a pair of spaced substantially Y-shaped frame members, a driven pulley pivotally mounted between said frame members and surrounding said power means, means connecting said power means and said driven pulley, gate legs pivotally mounted to the free ends of opposed legs of said Y-shaped frame members, an adjustable spring connecting said gate legs and frame members, a plurality of idler pulleys journaled in said frame members, a plurality of idler pulleys journaled in said gate legs, said driven pulley and idler pulleys being parallel and having common tangential planes, a continuous sanding belt positioned around said pulleys, a presser plate fastened to said frame members and positioned intermediate said frame members and said sanding belt, adjustable eccentric means for displacing the longitudinal axis of at least one of said idler pulleys, and adjustable handles secured to said frame members along the longitudinal axis of the center of gravity of said device in a transverse position with respect to said sanding belt.

4. In combination with a portable hand sander, having a pair of spaced substantially Y-shaped frame members, power means mounted between said frame members, a driven pulley pivotally mounted between said frame members and surrounding said power means, gate legs pivotally mounted to the free ends of opposed legs of said Y-shaped frame members, an adjustable bolt connecting said gate legs and frame member, a compression spring surrounding said bolt, a plurality of idler pulleys journaled in said frame members and gate legs parallel to said driven pulley and having common tangential planes with said driven pulley, a continuous sanding belt positioned around a presser plate fastened to said frame members and positioned intermediate said frame members and said sanding belt, and adjustable means for displacing the longitudinal axis of at least one of said idler pulleys, an anti-torque control comprising handles secured to said frame members along the longitudinal axis of said power means.

References Cited in the file of this patent UNITED STATES PATENTS 600,383 Sherwood Mar. 8, 1898 1,290,395 Steele Jan. 7, 1919 1,723,821 Swan Aug. 6, 1929 1,834,059 Hopkins Dec. 1, 1931 1,916,543 Welch July 4, 1933 2,060,266 Thompson Nov. 10, 1936 2,279,783 Fowler Apr. 14, 194-2 2,556,041 Pick June 5, 1951 2,560,102 Guinn July 10, 1951

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