US2171060A - Floor surfacing machine - Google Patents

Description

Aug. 29, 1939; G. DE SIPIRT 2,171,060

FLOOR SURFACING MACHINE F'iled Feb. 18, 1939 2 Sheets-Sheet l Aug. 29, 1939. G, 5 sPlRT 2,171,060

I FLOOR SURFACING MACHINE Filed Feb. 18, 1939 2 Sheets-Sheet 2 Giles D 01+ lm v Patented Aug. 29, 1939 UNITED STATES PATENT OFIE FLOOR SURFAGING MAGHINE Giles De Spirt, Toronto, Ontario, Canada Application February 18, 1939, Serial No. 257,067

4 Claims. 01. 51-177) The invention has for its primary object the production of a more efficient and serviceable Y grinding and polishing machine particularly adapted for terrazzo floors and the like, although it is not intended that its use shall be restricted to such work as the invention might be otherwise utilized.

A further object of the invention is to provide a machine of this class in'which a grinding and polishing head comprises a shoe revoluble about an axis and having several stones radially disposed and each mounted to gyrate about the orbit of the shoes as it turns. This is accomplished by a planetary gearing adapted to drive a complement of holding devices in which the stones are lodged.

The distinctive feature of gyrating the stones in the orbit of the shoe is that it increases the efficiency of the grinding andpolishing action and performs the surfacing operation in less time.

A still further object of the'invention. is to furnish the grinding and polishing head with a compensating mount having a rock or tilt enabling the stones to bear uniformly on a floor irrespective of any incidental unevenness that may exist in its surface. This compensating mount is also advantageous in a machine of the present type in which a pair of coacting heads are employed since the stones are caused to adjust themselves to the floor surface.

Having described the major objects of the invention, subsidiary objects and advantages will be evident from the ensuing description.

Referring to the accompanying drawings, Figure 1 is a side elevation of the machine embodying the invention.

Figure 2 is a front elevation showing the splash cover in section.

Figure 3 is a horizontal section taken on line 3-3 of Figure 2 depicting the left shoe with its cover removed to illustrate the planetary gearing.

Figure 4is a vertical section of one of the heads taken on line 44 of Figure 5.

Figure 5 is a fragmentary plan viewed on line 5-5 of Figure 4 omitting the driving shaft.

Figure 6 is a detail showing the main gear of the planetary set held against rotation by flexiblering or disc members.

Figure '7 is a plan of the underside of one of the holding devices with stones set therein.

Like numerals of reference denote similar parts in each figure of the drawings.

The conventional machine to which the invention relates comprises a horizontal frame 8 having the head structure, generally indicated by the numeral 9, at the front and a castor It] at the rear with a handle 5 l upwardly directed from the vicinity thereof for enabling an attendant to manipulate the machine over a floor surface I2.

Power is furnished by an electric motor I3 mounted upon the frame 3 and supplied with an encased chain drive it for operating gearing within the casing i5 whereby the vertical shaft l6 of each of the twin heads is driven at suitable speed. The shafts it are journalled in spaced housings ll projecting downwardly from the casing I5 and rigid with the same. Said shafts it operate in opposite directions but revolve at the same speed. The lower ends of the housings l? are flanged and. secured to a common plate it horizontally disposed and carrying the splash cover 20. Since the above construction is conventional it need not be described in greater detail.

The improved mechanism will now be recounted, which concerns the heads as already mentioned, there being two of these, each driven by a shaft I6. The heads are of identical construction, hence a description of one will suffice for the other.

The fixed plate It and. the shaft I6 constitute part of the head, the shaft It being a driving member and projecting well below the plate to afford a drive connection with a shoe 2!. The shoe 2| is a horizontal gear casing of substan tially triangular shape in plan and composed of separable top and bottom parts secured by fastening elements as at 22, the top part forming a cover for the bottom part. Centrally disposed in the shoe is a stub shaft 23 secured as at 24 in a boss 25 and projecting upwardly to meet the shaft IS with which it is aligned. Shaft 23 is keyed as at 20 so as to turn as a unit with the shoe 2|.

The meeting ends of shafts I6 and 23 are interlocked such as to provide a driving connection and at the same time-enable theshoe 21 to have a slight rock or tilt. This is shown as effected by a tongue and groove connection 21', the tongue being rounded at its terminus and the groove being likewise shaped. The coupling of the shafts could of course be achieved by other known expedients in the art that provide a flexible connection.

The gearing within the shoe is comprised of a stationary main gear 28 in mesh with three planetary gears 29 located. equidistantly therearound and rigidly united with shafts 30 of holding devices 3! that carry the grinding and polishing stones 32. The shaft 3|] of each planetary gear is vertically journalled in the shoe 2| preferably by means of antifriction bearings such as to take care of upward thrust due to pressure of the stones upon the floor surface.

The main gear 28 has a bore in a hub 33, and the shafts l6 and 23 fit in this bore, the shaft l6 having sufficient clearance to enable the shoe to rock as aforesaid. The shoe 2| is entirely journalled on the main gear 28 and to this end has a boss 34 encompassing the hub 33 and in addition to which is furnished with an anti-friction bearing to take upward thrust-see Figure 4.

The main gear is secured to a sub-plate 35 spaced below the plate l9 and connected. by fastening elements to the hub 33. The sub-plate 35 is preferably circular in extent and is supported by a plurality of arms 36 depending from: the plate I9 and having inturned ends forming shoulders that are engaged with the bottom face of the sub-plate 35. A series of helical compression springs 31 are interposed between the plate l3 and sub-plate 35 and circularly spaced about the shaft I6. The springs 31, of which there are 1 preferably six in number, function to retain the sub-plate 35 normally in seated position upon the shoulders of the arms 36. This construction enables the shoe 2| to tilt or rock about the driving axis so that the stones 32 of the holding devices 3| may bear evenly upon the floor surface.

Discs or rings of rubber or similar flexible material, as indicated at 38, are disposed between the plate l9 and the sub-plate 35 to embrace the springs 37 which are inserted in openings. The discs or rings 38 are peripherally secured to said plates 9 and 35 by means of fastening devices 39 of which there are six in number equally spaced in circular arrangement. The fastening devices 39 alternately secure the discs or rings to the plate l9 and to the sub-plate 35, and thus provide a flexible connection that holds the main gear 28 against rotation and at the same time permits the shoe 2| to rock or tilt about the vertical driving axis. This consruction also has the advantage of cushioning the drive so as to reduce shock and jar and to produce a smooth operating unit.

It will be evident from the preceding descrip-' tion that operation of the shaft I6 of the head bodily rotates the shoe 2| and since the main gear 28 is stationary, the planetary gears 29 are revolved about their several axes at comparatively high speed. Accordingly the holding devices 3| are rotated for causing circular motion of the stones 32 thereof in the orbit of rotation of the shoe 2|. In this manner the grinding and polishing action is promoted and expedited. As shown in Figure '7, the stones 32 are lodged in angular slots in the holding devices 3| and retained by wedges, there being several stones to each holder. As the shoe 2| revolves, the spring of the compensating mount functions to enable the holding devices to bear uniformly upon the surface being processed and accommodate incidental unevenness of such surface.

It will be understood that as there are two heads to the machine both are similar in operation, although one rotates in opposite direction to the other, the heads being disposed in juxtaposition and arranged to overlap in their sweep as will be evident from an inspection of Figure 3.

What I claim is:

1. In a machine of the class described, a head comprising a fixed support, a. driving shaft extending therefrom, a shoe extending transversely of the shaft, means extending radially of the shaft and providing a concentric journal for the shoe, retaining devices seating said means, springs urging said means against said retaining devices in an outward direction to counteract thrust on the shoe, and means providing a flexible connec- 7 tion between the driving shaft and the shoe.

2. In a machine of the class described, a head comprising a fixed support, a driving shaft extending therefrom, a shoe disposed transversely of the shaft, a plate spaced from said fixed support, means rotatably suspending the shoe from the plate coaxially with said shaft, means sustaining the plate from said fixed support, springs applying pressure upon the shoe to counteract thrust thereon, and means providing a flexible connection between the driving shaft and the shoe.

3. In a machine of the class described, a head comprising a fixed support, a vertical driving shaft journalled in the support and projecting therebelo-w, a horizontal shoe, an element carrying the shoe for rotation concentrically with the driving shaft and including a plate spaced below the fixed support, said plate encircling the driving shaft, a retaining mechanism depending from the fixed support and sustaining the plate in a manner to enable it to tilt, springs distributed around the plate to exert downward pressure thereon, and means providing a power transmitting connection between the driving shaft and the shoe, said means, being constructed to permit the shoe to tilt with the plate aforesaid.

4. In a machine of'the class described, a head comprising a frame including a horizontal plate, a vertical shaft journalled in the frame and projecting below the horizontal plate, means for driving the shaft, a horizontal shoe, a main gear therein upon which the shoe is journallecl, said gear having a bore receiving the vertical shaft, a stub shaft secured to the shoe and projecting upwardly from the bottom thereof within said bore to meet the said vertical shaft, means interlocking the meeting ends of the shafts and permitting a universal movement of the stub shaft, planetary gears journalled in the shoe and meshed with the main gear, holding devices rotated by the planetary gears, stones therein, a disc or ring secured to the main gear at the top of the shoe and encircling said vertical shaft, arms depending from the aforesaid horizontal plate and having parts supporting the disc or ring, compression springs interposed between the horizontal plate and disc. or ring to maintain the shoe in a yieldable manner whereby it may recede under pressure, a pliant ring encircling the vertical shaft and having said springs lodged in apertures therein, and fastening devices alternately securing the pliant ring to the horizontal plate and to the disc or ring.

GILES DE SPIRT.

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