US2289481A - Portable belt abrading machine - Google Patents

Description

July 14, 1942. A. c. BURLEIGH PORTABLE BELT ABRADING MACHINE 'Filed Dec. e, 1940 bym Patented July 14, 1942 UNITED STATES ATENT OFFICE PGR-TABLE BELT' ABRADENG .MACHINE Arthur C. Burleigh, Wellesley, Mass.

Application December 6, 19,40-, Serial No. 368,745

(Cl. 5-1-l7t) 6 Claims.

This invention relates to a portable belt abrading machine and particularly to an abrading machine of this type in which the motor for operating the belt is located within the supporting frame and between the upper and lower runs of the belt. This construction has the advantage that it results in a very compact machine with a relatively low center of gravity.

rI'he `features wherein my improvements reside will be more fully hereinafter set forth, and then pointed out in the appended claims.

In the drawing:

Fig. 1 is a sectional view through a sanding machine embodying my invention, taken on substantially the line .I-I, Fig. 2.

Fig. 2 is a section on the line 2 2, Fig. 1.

Fig. 3 is a section on the line 3-3, Fig. 1, the tension pulley being shown in elevation.

Fig. 4 Yis a section on lthe line II--4, Fig. l.

Fig. 5 is a section on the line 5-5, Fig. 1.

In the drawing, the abrading belt, which is indicated at I, passesaround a driving Lpulley 2 and an idler pulley 3, both of which are mounted on a suitable frame 4, the driving pulley 2 being at the rear end of the frame and the idler pulley 3 being at the front end thereof. This frame is formed with two side members 5 and 6 which are connected by a top or hood member 1 that covers the belt and pulley, and also `by a bottom member 8 which is shorter than the frame and underneath which the lower run or operative portion I2 of the abrading belt passes, said bottom mem* ber 8 thus forming a presser member for holding said operative portion 4of the abrading belt against the work. The side member 6 is relatively short and is situated mid-way of the frame between the driving `pulley 2 and the idler pulley 3.

The motor for operating the driving pulley 2 is indicated at 9. ing I0 which is situated within the frame between the bottom member 8 and the hood or ytcp member 'I, and between the upper run II and lower run |32 of the abrading belt I. This motor housing is shownas extending between the side members 5 and -6 and as connected thereto.

The motor shaft is indicated at I3. It extends transversely of the fra-me, and one -end of it is journaled inthe bearing I4 carried by the motor housing, and the .other end is journaled in the -I bear-ing I5 carried by the side member 5 of the frame and extends through said side member.

The driving connections between the motor shaft `*I3 and the driving pulley 2 comprise a This is mounted in a motor housan intermediate gear Il mounted on a stud I8 carried by the frame side mem-ber 5, said intermediate gear in turn meshing with a driving gear I 9 fast on the shaft 23 on which the pulley 2 is mounted. This shaft 20 is journaled in suitable bearings 2l, 22 carried by the side portion 5 of the frame, the end 23 of the shaft extending beyond the bearing 22 and having mounted thereon the hub 24 of the pulley 2, which hub is located centrally of the pulley. A

The idler pulley 3 is supported on an arm 55 which is secured to `and extends `forwardly from the motor housing Ill. For this purpose, said idler pulley is made in two sections 3a and 3b, each` of which is secured to the end of a shaft 52 which is journaled in the hub portion 53 with which the arm 55 is provided at its outer end. The inner ends of the pulley sections 3a, 3b overlie the ends of the hubs and hence the pulley sections are only separated from each other by a distance equal to the transverse dimension of the arm 55. I will preferably provide ballbearings 54 in the hub 53 for the shaft 52.

The frame or housing is provided with a handle 28 by which it may be manipulated, and this handle may conveniently have a switch element 29 for opening and closing the motor circuit.

The bottom portion 8 of the frame extends below the lower edge 35 of the side member 5, as shown by dotted lines in Fig. 1, so that when the machine is placed on the surface to be sanded pinion I 6 on the motor shaft which meshes with 55 or polished, the weight of the machine comes on the lower run of the abrading belt I. The side member 5 is provided with a bulge or extension i 3I at its rear lower cover which is situated to the .yieldingly held against the belt. This tension pulley is mounted on the motor housing I6, for which purpose a supporting bracket 33 is provided whichis secured to said motor housing. The tension pulley 32 is made in two sections, 32a and 32h, said sections being rotatably mounted on a shaft 34 which is carried by an arm 35 that, in turn, is pivotally secured to the supporting bracket 33, as shown at 36. The upper end of the bracket 33 is forked and the pivotal shaft 36 is mounted in the arms of the fork. One end of the arm 35 is located between the arms of the forked supporting bracket 33 and is pivotally mounted on the shaft 36. This supporting arm 35 extends between the two pulley sections 32a, 32h and provides a central support for the shaft 34.

The arm 35 has a depending stem 31 formed at its lower end with an eye 38 through which extends a pin 39 projecting from and carried by the bracket 33. 40 indicates a spring surrounding the pin 39 and confined between the stem 31 and the bracket 33, said spring 40 thus operating to yieldingly hold the pulley section 32a, 32h against the abrading belt, thus maintaining it under proper tension.

The pulley 32 is not only a tension Pulley but also an alining pulley, in that it functions to maintain the belt properly lined up.

The supporting bracket 33 is secured to the motor housing l0 in such a way that said bracket can be turned about a horizontal axis extending fore-and-aft of the frame,'thereby to maintain connected to the lower end thereof, as shown at I 43, said link extending through the side frame 5 and having a screw-threaded end 43 on which is screw-threaded a thumb piece 44 that bears against the side frame 5. The link 42 is provided with a shoulder 45, and a spring 46 encircles the link and is confined between said shoulder 45 and the side member 5 of the frame.

By turning the thumb piece 44 in one direction or the other, the bracket 33 will be turned or adjusted about its pivot 4|, and thereby the axis I of the tension pulley 32 may be maintained in proper parallel relation with the axis of the idler 3.

I have also shown means whereby the yielding pressure of the tension pulley 32 against the belt may be reduced or entirely removed. Extending through the end of the pin 39 is a shaft 50 which has cam members 41 mounted thereon that bear against the outside of the arm 31. This shaft 50 extends through an opening 48 in the side portion 5 of the frame, and the outer end thereof is bent laterally as shown at 49 to provide a finger piece by which the shaft may be turned. When the shaft is turned counterclockwise in Fig. 1, the cams 41 act against the stem 31 and thus swing the arm 35 downwardly, which will result in relieving the yielding pressure of the tension roll 32 against the under side of the belt.

5| indicates a hand grip which is secured to the top member 1 and which provides means by which the person operating the apparatus can apply pressure thereto as needed for properly sanding the surface being treated.

This hand grip 5| not only provides means for applying pressure to the abrading machine, as above set forth but, together with the point 56 of the handle 28, it provides a three-point support on which the machine may be supported in inverted position, the two ends 51 of the hand grip 5| and the point 55 of the handle 23 providing the three points of support. When the abrading machine is thus supported in an inverted position and is set in operation, it can be advantageously used for sanding or polishing small pieces by holding the pieces against the exposed portion of the abrading belt when the machine is in its inverted position.

I claim:

1. An abrading machine comprising a frame, a driving pulley mounted thereon, an idler pulley, an abrading belt passing around said pulleys, a motor housing situated between said pulleys and between the upper and lower runs of the abrading belt, a motor mounted in said housing, driving connections between the motor and the driving pulley, a supporting bracket mounted on the motor housing for turning movement about a horizontal axis extending fore-and-aft of the frame, a tension pulley yieldingly mounted on said bracket and engaging the abrading belt, and means for adjusting the supporting bracket about its axis to vary the angular relation between the tension pulley and the idler pulley.

2. An abrading machine comprising a frame, a driving pulley mounted thereon at the rear end thereof, an idler pulley at the front end of said frame, an abrading belt passing around said pulleys, a motor housing situated between said pulleys and between the upper and lower runs of the abrading belt, a motor mounted in said housing, driving connections between the motor and the driving pulley, a supporting bracket pivotally mounted on the motor housing to turn about a horizontal axis extending fore-and-aft of the frame, a tension pulley carried by said bracket, means for yieldingly holding the tension pulley against the abrading belt, and means for adjusting said bracket by turning it about its horizontal axls.

3. An abrading machine comprising a frame having two side members, a motor housing situated between and mounted on said side members, a motor in the motor housing, a single relatively large pulley carried by the frame at the rear end thereof, said pulley constituting a driving pulley, a forwardly extending arm secured to the motor housing, a relatively small idler pulley rotatively mounted on said arm and situated at the front end of the frame near the lower side thereof, an abrading belt passing around said pulleys, the motor housing being situated between the upper and lower runs of said belt, a supporting arm pivotally mounted on the motor housing at the front side thereof, a tension pulley carried by said arm and engaging the abrading belt and a spring acting on said arm and yieldingly holding the tension pulley against said belt.

4. An abrading machine comprising a frame having two side members, a motor housing situated between and mounted on said side members,

a motor in the motor housing, a single relatively large pulley carried by the frame at the rear end thereof, said pulley constituting a driving pulley, a forwardly extending arm secured to the motor housing, a relatively small idler pulley rotatively mounted on said arm and situated at the front end of the frame near the lower side thereof, an abrading belt passing around said pulleys, the motor-housing being situated between the upper and lower runs of said belt, a supporting arm pivotally mounted on the motor housing at the front side thereof, a tension pulley carried by said arm, a stem depending from said arm, and a spring interposed between said stem and the motor housing and operating to yieldingly hold the tension pulley against the belt.

5. An abrading machine comprising a frame having two side members, a motor housing situated between and mounted on said side members, a motor in the motor housing, a single relatively large pulley carried by the frame at the rear end thereof, said pulley constituting a driving pulley, a forwardly extending arm secured to the motor housing, a relatively small idler pulley rotatively mounted on said arm and situated at the front end of the frame near the lower side thereof, an abrading belt passing around said pulleys, the motor housing being situated between the upper and lower runs of said belt, a supporting bracket pivotally mounted on the front side of the motor housing to turn about a horizontal axis extending fore-and-aft of the frame, an arm pivotally mounted on said bracket to turn about a transverse horizontal axis, a tension pulley carried by said arm, said arm having a depending stern, a spring interposed between said stern and said bracket for holding the tension pulley yieldingly against the belt, and means for adjusting the bracket about its horizontal axis.

6. An abrading machine comprising a frame having two side members connected by a top member in the form of a hood having downwardly directed end portions, a driving pulley and an idler pulley mounted on the frame, an abrading belt passing around said pulleys, the upper run of said belt passing underneath the hood, a motor housing carried by the frame and situated between said pulleys and between the upper and lower runs of the abrading belt, a motor in said motor housing, driving connections between the motor and the driving pulley, a handle mounted on said hood at the rear end thereof, and a hand grip separate vfrom the handle and mounted on said' hood adjacent the front end thereof, said hand grip presenting a bar extending transversely of the hood and having a concavely curved upper surface, the two ends of said bar together with the handle forming a three-point support for the abrading machine when it is in inverted position.

ARTHUR C. BURLEIGH.

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