US3325948A

US3325948A - Belt sander

Info

Publication number: US3325948A
Application number: US351134A
Authority: US
Inventors: Ronald E Gronke
Original assignee: Skil Corp
Current assignee: Skil Corp
Priority date: 1964-03-11
Filing date: 1964-03-11
Publication date: 1967-06-20
Anticipated expiration: 1984-06-20

Description

R. E. GRON-KE v June 20, 1967 BELT SANDER 2 Sheets-Sheet 1 Filed March 11, 1964 INVENTOR. RONALD E GQONKE United States Patent 3,325,948 BELT SANDER Ronald E. Granite, Des Plaines, 111., assignor to Skil Corporation, Chicago, 111., a corporation of Delaware Filed Mar. 11, 1964, Ser. No. 351,134 3 Claims. (Cl. 51-441) This invention relates generally to portable, powered belt sanders, and more particularly to new and improved dust pickup and motor cooling construction for such sanders.

It is a primary object of the present invention to provide a belt sander having new and improved dust pickup and motor cooling construction, which construction contributes to balanced design of the sander thereby making the same easy to manipulate or maneuver by hand.

It is a further object of the present invention to provide in a belt sander of the type described, a double vane fan and associated housing construction of new and improved design for effectively cooling the sander motor and collecting dust at the vicinity of one of the rollers of the sander.

It is another object of the present invention to provide a belt sander in accordance with the above mentioned objects and including further a housing having a vertical fiat side coplanar with an edge of the sanding belt so as to adapt the belt sander for sanding marginal portions of surfaces which are bordered by walls or ledges, for examle. P These and other objects and advantages of the invention will become apparent from the following specification disclosing a preferred embodiment of the invention which is illustrated in the accompanying drawings.

In the drawings:

FIG. 1 is a side elevational view of one form of the belt sander of this invention;

FIG. 2 is a rear elevational view of the sander with a portion of the same broken away so as to show a passageway associated with the dust pickup construction;

FIG. 3 is an enlarged fragmentary section taken generally along line 33 of FIG. 1;

FIG. 4 is an enlarged perspective view of a member forming an end wall of a motor enclosing portion of the sander housing;

FIG. 5 is a section taken along line 5-5 of FIG. 4; and

FIG. 6 is a section taken along line 66 of FIG. 3.

Referring now to the drawings, the belt sander of this invention includes a housing characterized by a lower elongated portion 10 and an upper, cylindrical, transversely extending portion 12. Housing portion 10 includes suitable means rotatably supporting transversely thereof a pair of parallel spaced rollers 14 and :16. Lower housing portion 10 also includes a shoe 18 mounting a pad 20 which supports the lower run of a flexible sanding belt 22 trained over both

rollers

14, 16, which belt has a width substantially the same as the length of the rollers. Housing portion 16 mounts a fixed fiat guide bar 24 which engages one edge of belt 22 for locating the same laterally of the sander during installation. Front roller 16 is resiliently supported in housing portion 10 by means including suitable spring means (not shown) for urging this roller forwardly so as to maintain belt 22 tight. The means for supporting roller 16 include a snap bracket 26 mounting roller 16 so as to permit the latter to be snapped rearwardly for belt removal and replacement. The means supporting belt 22 are described for purposes of illustration only as this construction of itself forms no part of the present invention; other suitable means may be provided for supporting a sanding belt such as belt 22.

Lower housing portion 19 is open at one side thereof 3,325,948 Patented June 20, 1967 (the near side as seen in FIG. 1), which open side is defined by a housing edge 28 which is contained in a vertical plane with common ends of

rollers

14, 116 being coplanar with housing edge 28. The other side of lower housing portion 10 is closed by a wall 29 which serves, among other things, to support the shafts rotatably

mounting rollers

14 and 16.

Cylindrical housing portion 12 includes an end wall 30 (FIG. 3) provided with a plurality of suitably spaced vents 32 (FIG. 2) which extend into the interior of housing portion 12. Wall 30 is secured to housing portion 12 by a number of fasteners 33 (FIG. 2). The other end of cylindrical portion 12 is defined by a circular plate 34, which plate includes a number of integral lugs 36 (FIG. 4) defining arcuate shoulders 38 which fit within the end of cylindrical housing portion 12. Plate 3-4 is secured to housing portion 12 by a number of fasteners 40 (FIGS. 1 and 2) extending through suitable apertures in ears 42 of plate 34 and threadingly engaging suitable threaded bores (not shown) in housing portion 12. Lugs 36 define with the end of housing portion 12 a plurality of openings 44 (FIG. 3) which permit discharge of the airflow for cooling the motor as will be explained hereinbelow. Plate 34 includes a planar exterior surface having a number of parallel horizontally extending recesses 46 provided therein. These recesses do not extend through plate 34; they are provided for ornamentation purposes only. The outer face of plate 34 characterized by these recesses is coplanar with edge 28 of lower housing portion 10 for a purpose to be explained hereinbelow.

An electric motor 48 of suitable construction has its stator secured in housing portion 12 by fasteners 49. The motor includes a rotor shaft 50 having one end thereof supported in a bearing 52, which bearing is mounted in a central recess 54 formed integrally with plate 34 on the inside center portion thereof. The other end of shaft 50 is rotatably supported in a bearing 56, this bearing being supported in an aperture 58 formed in end wall 30 of housing portion 12. Motor 48 includes the usual commutator 60 having brushes 62 held against the same by associated springs 64, the brushes and springs being mounted in brush holders 66 received in suitable cavities in housing portion 12 and held therein by fasteners 68.

The end of motor shaft 50 adjacent bearing 56' extends outwardly of housing wall 30 and non-rotatably mounts a drive wheel 70 including fixed-together

parts

70a and 70b. Wheel 70 includes on its outer surface a number of parallel spaced grooves engaging complementary shaped ribs on the inside surface of a drive belt 72. Drive belt 72 is trained over a driven wheel 74, which driven wheel is provided on its exterior with spaced axially extending grooves for complementary engagement with the ribs on belt 72 so as to prevent slippage with the latter. Driven wheel 74 includes fixed together parts 74a, 74b, part 74b being non-rotata'bly mounted on one end of a shaft 78. Shaft 78 is journaled at its midpoint in a sleeve 80, which sleeve is supported in a bore 82 formed in a housing wall 84, which wall cooperates with a shell member 85 to define an enclosure for

wheels

70, 74 and belt 72. The other end of shaft 78 is journaled in a sleeve 86 mounted in an opening 88 formed in lower housing wall 29. Shaft 78 includes an annular series of teeth 90, which teeth are in meshing engagement with complementary shaped teeth on a gear 91. Gear 91 is fixedly mounted on a shaft 92 which is journaled in

bearings

93, 94 supported in openings in respective walls 29, 84. Shaft 92 is fixed to and supports roller 14. It should be apparent that energizing of motor 48 serves to rotate roller 14 thereby to drive belt 22. Belt 22 is driven in a direction so that the lower run thereof moves rearwardly of housing 10, i.e. toward roller 14.

Cylindrical housing portion 12 includes a rearwardly extending piston grip portion 96 supporting a trigger 98. Pistol grip portion 96 also serves as attaching means for one end of an electrical cord 100, which cord contains the usual lead wires extending to the electric motor through a switch (not shown) operated by trigger 98. Housing portion 12 also includes an auxiliary or forward handle 102, thereby adapting the belt sander to be grasped by both hands of an operator.

A double vane fan 104 is mounted on an enlarged portion 50a of shaft 50 adjacent the end thereof journaled in sleeve 52. Fan 104 includes a central web 105 having formed onone side thereof a first set of radially extending vanes 106 and having formed on the other side thereof a second set of radially extending vanes 108. End plate 34 includes an annular wall 110 which serves as a supporting surface for an annular baffle plate 112, the baflie plate being secured to wall 112 at marginal portions of the former by suitable fastening means (not shown). Annular baffie plate 112, which includes a central opening 112a, defines with the inside walls of plate 34 a dust collecting chamber 114. Annular baffle plate 112 also defines in housing portion 12 a motor enclosing chamber 116. A second annular plate 118 is secured in housing portion 12 in close parallel spaced relation with the web of fan 104. Baflle plate 118 includes a central opening 118a. Web 105 of fan 104 defines with

baffle plates

112, 118 a pair of

fan spaces

119a, 11%.

Referring now to FIGS. 46, plate 34 includes an integral, upstanding portion or stack 120 defining a vertically extending discharge passageway 122 which opens at one end thereof into fan space 119a and which opens at the other end thereof at the top of stack 120 at an enlarged portion 122a. Stack 120 is externally threaded as at 124 for threading engagement with a collar 126 rotatably attached to one end of a conduit 128, the end of which conduit extends to a dust collecting bag 130. It will be understood that collar 126 serves as a means for detachably securing conduit 128 and the dust bag to stack 120 for communicating passageway 122 with the interior of the dust collecting bag.

A shell 132 is secured in overlying relation on the rear end of housing portion by fasteners 133 (FIG. 2), which shell includes a resilient pad 134 extending transversely of the sander housing for supporting the rear end thereof. Shell 132 defines with the exterior of housing 10 at the rear portion thereof a passageway 136 opening at one end thereof in the vicinity of roller 14 just rearwardly of the latter. It will be understood that this opening adjacent roller 14 extends completely along the length of the same. Passageway 136 funnels into a reduced tubelike portion 132a which interfits with a complementary shaped tubular portion 138 integral with end wall 34. Tubular portion 138 includes a passageway 138a (FIG. 3) communicating passageway 136 with dust collecting chamber 114.

During operation of the belt sander for performing a sanding operation, fan 104 causes a flow of air through

passageways

136, 138a, dust collecting chamber 114, opening 112a, fanspace 119a, passageway 122 and conduit 128 into bag 130. This flow of air picks up dust or the like carried rearwardly by the lower run of belt 22 and carries the dust into bag 130. Rotation of fan 104 also causes a flow of air through vent openings 32, motor enclosing chamber 116, opening 118a, fan space 1191) and outwardly through openings 44. This flow of air cools electric motor 48. Thus, double vane fan 104 se-rvesboth to cool motor 48 and collect dust formed by the action of the sanding belt.

It will be appreciated that the location of fan 104 and its associated housing construction on the side of the belt sander housing opposite the side thereof supporting the drive means between the motor and one of the rollers serves to balance the belt sander thereby making the latter easier to manipulate or maneuver. As the outer surface of plate 34 is coplanar with lower housing edge 28 and common ends of

rollers

14 and 16 which support belt 22, the sander of this invention may be used to sand marginal portions of a surface bordered by a ledge or wall for example. In other words, in sanding a floor, for example, the edge or margin of the floor may be sanded as the sander has no overhanging parts along the open side thereof so as to prevent the sander from being brought into contact with a baseboard or wall bordering the floor being sanded.

It should be noted that baffle plate 112 acts to improve the airflow from the dust collecting chamber so as to improve the efficiency of the fan in collecting dust and forcing the same into bag 130.

While the invention has been shown in but one form it will be obvious to those skilled in the art that it is not to be so limited. On the contrary the invention is susceptible to various forms and modifications without departing from the spirit and scope of the appended claims.

I claim:

1. In a belt sander, in combination, an elongated housing having means supporting a pair of rollers transversely of the housing and in parallel spaced relation, said housing including a transversely extending motor enclosing portion which is provided with vents in one end thereof, said housing having a vertical planar side with common ends of said rollers and theother end of said motor enclosing portion being substantially coplanar with said planar side, an electric motor supported in said motor enclosing portion axially of the same, said motor having the end thereof adjacent said one end of the motor enclosing portion in driving engagement with one of said rollers by means which extend along the side of said housing opposite said planar side thereof, said housing including means defining a passageway opening at one end thereof in the vicinity of one of said rollers and opening at the other end thereof into said motor enclosing portion adjacent said other end thereof, said housing including discharge passageway means opening into said motor enclosing portion adjacent said other end thereof, a double vane fan mounted insaid motor enclosing portion in close spaced relation with said other end thereof and driven by said motor for rotation about an axis extending transversely of the housing, said fan being effective to cool said motor and to evacuate dust in the vicinity of said last mentioned roller.

2. In a belt sander, in combination, an elongated housing having means supporting a pair of rollers transversely of the housing and in parallel spaced relation, said housing including a transversely extending cylindrical portion which is provided with vents in one end thereof, an annular baffie plate mounted in said cylindrical portion perpendicular to the central axis thereof and in close spaced relation with the other end of the cylindrical portion thereby defining a motor enclosing chamber and a dust collecting chamber, said housing having a vertical planar side with common ends of said rollers and said other end of said cylindrical portion being substantially coplanarwith said planar side, an electric motor supported in said motor enclosing chamber axially of the same, said motor having the end thereof adjacent said one end of the cylindrical portion in driving engagement with one of said rollers by means which extend along the side of said housing opposite said planar side thereof, said housing including means defining a passageway opening at one end thereof in the vicinity of one of said rollers and opening at the other end thereof into said dust collecting chamber, a double vane fan in said motor enclosing chamber driven by said motor for rotation about said axis in close spaced relation with said baffle plate, said cylindrical portion including discharge passageway means opening into said motor enclosing chamber adjacent said baffle plate, said fan being effective to cool said motor, and said fan also being effective to evacuate dust by drawing the latter from the dust collecting chamber through the opening defined by the baffle plate and then into the discharge passageway means.

3. In a motor driven belt sander of the type including dust pickup means, wherein the sander includes an elongated housing portion supporting a pair of transversely extending belt carrying rollers, the improvement which comprises, a motor and housing means enclosing and supporting the former transversely of said elongated housing portion, which housing means has opposite ends generally coterminous with sides of said elongated housing portion, a double vane fan carried by one end of said motor in a corresponding end of said housing means, drive means connecting the other end of said motor with the corresponding end of one of said rollers, discharge passageway means opening into said housing means at said corresponding end thereof and vent means in the other end of the housing means, and further passageway means References Cited UNITED STATES PATENTS 8/1934 Myers 51-l70.4 4/1965 Burrows et al. 51-1704 ROBERT C. RIORDON, Primary Examiner.

L. S. SELMAN, Assistant Examiner.

Claims

1. IN A BELT SANDER, IN COMBINATION, AN ELONGATED HOUSING HAVING MEANS SUPPORTING A PAIR OF ROLLERS TRANSVERSELY OF THE HOUSING AND IN PARALLEL SPACED RELATION, SAID HOUSING INCLUDING A TRANSVERSELY EXTENDING MOTOR ENCLOSING PORTION WHICH IS PROVIDED WITH VENTS IN ONE END THEREOF, SAID HOUSING HAVING A VERTICAL PLANAR SIDE WITH COMMON ENDS OF SAID ROLLERS AND THE OTHER END OF SAID MOTOR ENCLOSING PORTION BEING SUBSTANTIALLY COPLANAR WITH SAID PLANAR SIDE, AN ELECTRIC MOTOR SUPPORTED IN SAID MOTOR ENCLOSING PORTION AXIALLY OF THE SAME, SAID MOTOR HAVING THE END THEREOF ADJACENT SAID ONE END OF THE MOTOR ENCLOSING PORTION IN DRIVING ENGAGEMENT WITH ONE OF SAID ROLLERS BY MEANS WHICH EXTEND ALONG THE SIDE OF SAID HOUSING OPPOSITE SAID PLANAR SIDE THEREOF, SAID HOUSING INCLUDING MEANS DEFINING A PASSAGEWAY OPENING AT ONE END THEREOF IN THE VICINITY OF ONE OF SAID ROLLERS AND OPENING AT THE OTHER END THEREOF INTO SAID MOTOR ENCLOSING PORTION ADJACENT SAID OTHER END THEREOF, SAID HOUSING INCLUDING DISCHARGE PASSAGEWAY MEANS OPENING INTO SAID MOTOR ENCLOSING PORTION ADJACENT SAID OTHER END THEREOF, A DOUBLE VANE FAN MOUNTED IN SAID MOTOR ENCLOSING PORTION IN CLOSE SPACED RELATION WITH SAID OTHER END THEREOF AND DRIVEN BY SAID MOTOR FOR ROTATION ABOUT AN AXIS EXTENDING TRANSVERSELY OF THE HOUSING, SAID FAN BEING EFFECTIVE TO COOL SAID MOTOR AND TO EVACUATE DUST IN THE VICINITY OF SAID LAST MENTIONED ROLLER.