US2193418A - Surfacing machine - Google Patents

Description

12, 1940. E. Bv. GEORGE y 2,193,418

SURFACING' MACHINE Filed June 14, 1937 521 'A 'l fwezzn'. 11 vWah/21125)5"690,7:96,

Patented Mar. l2, 1940 UNITED `STATES PATENT OFFICE y Edward B. George, Chicago, Ill. Application June 14, 1937, Serial No. 148,056

4 Claims.

This'invention relates to surfacing machines of the general type adapted for the smoothing and finishing of at surfaces of metal, wood, or other ccmposition. g

Machines for this general purpose, both pneumatically and electrically driven, -are common, but one of the objections to their use resides in the fact that the position of the surfacing pad relatively to the surface being worked is dependent to a large degree upon the position in which the body of the tool is held by the operator, and if it be tilted in one direction or the other, thesurfacing pad is likewise tilted so as to operate more rapidly at one edge than the other, producing resultant unevenness in the surface being finished.

One of the primarypurposes of my present invention is to provide for such an extent of ilexibility between the body of the tool Aand the surfacing pad that the pad will rest -evenly and operate uniformly upon the surface being worked, regardless of any tilting within reasonable limits of the body of the machine.

Another purpose of the. invention is to provide a driving connection between the motor on the body and the surfacing pad of such flexibility that it will not be affected nor its operation impaired or restricted by any relative tilting movements between the body and the pad.

Another purpose isto provide a driving connection for the pad which will be substantially frictionless and which will be capable of operating for prolonged perio'ds without appreciable wear.

Another feature of the invention resides in the connection between the working pad and the body of the machine which is designed to ab-A sorb the reciprocatory and vibratory movements of the pad so that they are not transmitted t the body of the tool, and consequently the operator who grasps or holds the body is not .subjected to these annoying movements.

Other objects and advantageous features of my invention will be later apparent as the same beccmes better understood by reference to the following description when considered in connection with the accompanying drawing.

Referring to the drawing,

Fig. lI is a side elevation of a machine embodying the principles of my invention, the lower central portion being shown in section;

Fig. 2 is a sectional view o n the line 2-2 of Fig. 1; and

Fig. 3 is a sectional view on the line 3-3 of Fig. 1.

Referring to the drawingmore in detail, reference character 5 indicates the motor base of the machine which in the present instance consists of a dat metal plate, although in heavier machines than that here illustrated thev base would (ci. 51-17m plate II by screws I3 and to the bottom of the base 5 by similar screws I4, metal inserts I5 being embedded in the tubes I2 at top and bottom. for the reception and anchorage of the screws' I3 and I4..

A resilient rubbing pad I6 of sponge rubbery or other suitable material is disposed beneath. the pad plate II and has its lower4 face,` which is slightly arcuate as shown, covered by a sheet I'l of abrasive` material the character of which depends upon the material of the surface to be finished and the neness of the nish desired. This abrasive sheet is fastened to the pad plate II by a pair of cross bars I8 and I9, respectively, yieldably connected by coiled tension springs ZI and 22` which cause the abrasive sheetto be clamped between the cross bars and the upwardly curved ends 23 of the pad plate. nection between the cross bar I9 and the ends of the springs 2l and 22 includesa loop 24 serving as a grip which can be engaged by the lthumb and fingers of the operator to pull the bar I8 to the left (viewing Figs. land 2) so as' to free it from the groove of the pad plate, thereby releasing the abrasive sheet.

The depending lower end 25 of the vertical motor has xed thereto by a set screw'26, or otherwise, a downwardly projecting stud 21 which has a driving t in a -circular eccentric member 28 having its periphery grooved to form the inner race of a ball bearing including the balls 29 retained between the inner race and an outer race 3'I. It Will be apparent that since the eccentric member 28 is rigidly connected to the shaft 25, it will revolve about the axis of the shaft as a center when the motor is set in operation.

A guideway fixed to the pad plate and straddling the outer race member 3l affords a driving connection between the motor and the pad plate which causes this plate to reciprocate longitudinally of the motor base under the inuence of the rotating motor shaft. Thisguideway comprises the transverse upstanding walls 32 and 33 Vspaced apart a distance equal to the external diameter of the outer ball race member 3|, as will be apparent from Figs. 1 and` 2, and this member, as will be seenfrom Figs. land 3, is slightly arcuate vertically onits outer surface so lthat a substantially line contact and theoret- The con-v ically a point contact is established between this raceway and the guideway members 32 and 33. For purposes of strength and rigidity the ends of the guides 32 and 33 are connected by end walls 34 and 35. n

For the purpose of protecting the moving parts of the ball bearing from the injurious effect of dust and abrasive material produced by operation of the tool, a iexible tubular housing 36 em'- braces at its lower end the guideways and at its upper end the collar 31 of the motor housing.

Obviously this flexible protector does not interfere with the relative tilting movements between the pad plate and the motor base.

It should be manifest that the flexible tubula connections i2 between the motor base and the pad plate yleldingly support the weight of the motor upon the pad plate and yieldingly transmit to the pad plate downward pressure exerted upon the motor. The vertical movements of the motor relatively to the pad plate being slight, such relative vertical movements do not interfere with the driving connection between the motor and the pad since the race member 3i and the parts by which it is carried simply move up and down in the pad plate guideway. The flexible tubular connections I2 furthermore permit longitudinal reciprocatory movements of the pad plate without transmitting these move,- ments to the motor.` The ultimate and desirable result is that the pad plate may be very rapidly reciprocated longitudinally and more or less pressure may be applied thereto by the operator, as desired, without the transmission of any appreciable amount of either the vibratory or reciprocator.movements of the plate to the motor which is manually manipulated and moved about by the operator. For convenience the motor is equipped with suitable handles to be grasped by the operator. The curved handle 33 and the straight handle 39 being both attached to a yoke 4i secured to the motor. Other means of attaching the handles may obviously be resorted to. Handle 38 also carries in convenient position a switch lever or button 42 of an electric switch by manipulation 0f which the motor may be started the line contact drive between this member 3i and the guide members 32 and 33.

My invention provides a surfacing machine possessing extreme flexibility and permitting the -a vertically disposed electric motor provided with abase plate, a. surfacing pa`d, a plurality of flexible members extending transversely of the pad and connected 'therewith and to said base plate, said members affording a exible connection between the motor and the pad permitting relative movements between the motor and pad.

an upwardly opening guideway secured tothe upper face of said pad, an eccentric'flxed to the motor shaft and disposed in said guideway, the

eccentric being vertically movable in said guide- 'lo of a surfacing pad, a transversely extending guideway comprising parallel walls projecting upwardly from said pad, a pair of transversely disposed, iiexible members secured to said pad, a? motor including a base plate, means for securely attaching said base plate to the tops of said flexible members, an eccentric carried by the motor shaft and projecting into said guideway, said eccentric being exteriorly curved in vertical plane to permit tilting movements of the motor relatively to the pad, said eccentric in conjunction with said guideway being adapted to impart 1ongitudinal reciprocatory movements to the pad relatively to the motor, said iiexible connecting members being adapted to permit such reciprocatory movements while preventing transverse movements of the pad and serving to absorb vibration between the pad and the motor, and said driving connection permitting vertical and angular movements of the motor relatively to the pad without disturbing the driving relation.

3. In a surfacing machine, the combination of a vertically disposed electric motor, a surfac ing pad, connections -between the ends of the pad and the base of the motor, including flexible members extending transversely of the pad and means forv securing said, members to the pad and tosaid motor base whereby the pad y is. held against llateral movement but is permitted to reciprocate longitudinally and to move vertically relative to the motor, and driving connections between the motor shaft and said pad, said connections being telescopic to permit relative vertical movements between the motr and pad and also being universally exible to permit tilting movements of the motor relatively to the pad in' any direction without disturbing the driving relation.

4. In a surfacing machine, the combination of a vertically disposed electric motor provided with a base, a surfacing pad, a plurality of flexible members extending transversely of the pad and connected therewith and to said base to provide a flexible vibration absorbing connection between the motor and the pad permitting rela-v tive movements between the motorl and pad, an open top guideway secured to the upper face of said pad, an eccentric driven by the motor and disposed in said guideway, said eccentric being vertically movable in said guideway and exteriorly curved to permit lateral tilting movements of the motor relatively to the pad without disturbing the driving relation, and a boot enclos- I ing said driving connection.

EDWARD B. GEORGE.

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