US2854798A - Sanding head - Google Patents

Description

Oct. 7, 1958 o. so; HAVEN 2,854,798

sANnING HEAD Filed Oct. 50, 1957 2 Sheets-Sheet 1 man-7,1958 o. s. DE HAvEN 2,854,798

SANDING HEAD Filed Oct. 30, 1957 2 Sheets-Sheet 2 #frag/vf rg -erating and at-rest conditions.

United States Patent C) SANDING HEAD Oliver S. De Haven, Indianapolis, Ind. Application October 36, 1957, Serial No. 693,365 Claims. (Cl. 51193.7)

This invention relates to a rotatable sanding head of the type employing a plurality of radially projecting strips of abrasive engageable with a work-piece and supported during rotation of the head by a plurality of radially projecting brushes.

Heretofore the abrasive strips in such sanding heads were either wound on a common spool or in separate coils lixedly retained in the sanding head. In either event, it was a cumbersome time-consuming task to replace the abrasive strips, and it required a complete stoppage of the equipment to manually feed fresh abrasive material from the spool or coils. In the common spool arrangement, only a relatively short supply of strips could be used, and the percentage of Waste was high. With the separate coil arrangement, non-uniform lengths of the abrasive strips were fed out which produced a poor quality sanding operation and also produced excessive waste.

It is the general object of my invention to provide a sanding head which will overcome the difficulties and disadvantages of the previous heads. More specifically, it is an object of my invention to provide a rotatable sanding head which is adapted to carry a plurality of spools of abrasive strips, which will permit the convenient and rapid replacement `of said spools, and which can be varied in width to take different widths of abrasive strips. It is another object of my invention to provide a rotatable sanding head which Will dispense abrasive strips simultaneously from all the spools of the head and will dispense uniform predetermined lengths of abrasive material from the individual spools, and which Will dispense said abrasive strips both while the head is rotating and while it is at rest.

ln accordance with my invention, the sanding head comprises a Vpair of end members or assemblies, conveniently in the form of spiders, adapted to be mounted in spaced relation on a rotating shaft. The end members are adapted to carry a series of brushes projecting from spaced points about the periphery of the head, and are further adapted to carry spools of abrasive strips inwardly of such brushes to feed abrasive strips to the leading faces of the brushes. The spools are removably mounted on spindles which are geared together, as by planetary gear means, or otherwise interconnected for simultaneous feeding movements, and means is provided to actuate the spools to feed abrasive strips therefrom. Preferably, the gear train between the spools is driven by relative rotation between the head and a drum carried with the head, as by means of a worm gear mechanism which advances the spool gears through a predetermined feeding movement for each actuation of the drum relative to the head. The drum may be rotated relative to the head either by retarding drum rotation when the head is rotating or by ,manually'rotating the drum when the head is at rest, so

that the feeding operation may be effected under both op- The spool gear train and Vof the spider 11, in a paired arrangement.

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the operating mechanism therefor are desirably carried with one of the end members or assemblies of the head, as a self-contained assembly, and the opposite end member or assembly is adapted to be mounted at different axial distances therefrom with the brushes and abrasive spools being supported between the two end members. Conveniently, the axial distance between the two end members can be varied to receive brushes and spools of different widths and thus to form heads of different axial widths.

Further objects and features of the invention will bccome apparent from the following description, and the accompanying drawings of a specific embodiment of the invention. In the drawings:

Fig. l is a central vertical section through a sanding head embodying my invention and taken on the line 1 1 of Fig. 2 to show portions thereof in elevation;

Fig. 2 is a vertical section taken on the line 2 2 of Fig. 1

Fig. 3 is a vertical section taken on the line 3-3 of Fig. l;

Fig. of Fig.

Fig. and

Fig.

arms.

The sanding head shown in the drawings comprises a pair of end members, or spiders 10 and 11, each having a plurality of radially extending arms 12 and 13, and a central mounting hole 14. The spider 10, shown in the drawings as the outer member of the head, is provided with an outwardly directed hub 16 in which the hole 14 is formed and by which the spider 16 mounted on a rotatable driving shaft 15. The inner spider 11 has a central hub 17 provided with the hole 14 and is carried on a sleeve 18 mounted on the shaft 15 and provided with an annular end flange 19. The spider 11 is axially positioned on the sleeve 18 by a shoulder 20 against which the inner face of the spider 11 abuts.

The spider 10 is spaced axially along the shaft from the sleeve 18 and hence from ,the spider 11 by a spacer sleeve 2l of a length to give the desired spacing between the two spiders. By using different lengths of spacers 21 the spiders 10 and 11 can be disposed at different axial distances from each other to vary the axial length of the head.

The head is retained on the shaft 15 by a nut 24 threaded on the outer end of the shaft and adapted to be tightened against the hub 16 of the spider 10 to clamp the parts together on the driving shaft, between itself and a shoulder 25 formed on the driving shaft 15.

Each arm 12 of the spider 10 lies opposite an arm 13 A rigid arms 12 4 is a vertical section taken on the line 4-4 1; 5 is a isometric view of one of the brush holders;

6 is a fragmental side view lof one of the spider channel member 28 extends axially between the 'and 13 of each pair and is supported thereby. Desirably,

each member 28 is a double channel formed with its legs 29 converging from the edges of a pair of webs 30 disposed in back-to-back relationship. While single channels might be used in heads of short axial length the preferred double channels reduce the tendency of the channels to warp under the centrifugal force generated during operation of the head, especially when the head width has been increased by the use of a relatively long spacer 21.

The channels 28 are mountedon the spiders 10 and 11 by means of end plates 31 having tapped holes 32 ,for the reception of screws 33 extending through the spider arms 12 and 13. Conveniently, the arms are provided with a plurality of holes 34 through which the screws may extend, so that by placing the screws 33 in the desired holes 34 to the channels 28 may be mounted on the spider arms at the desired angle. Desirably, one of the end plates 31 extends over only the inner pair of channel legs29 leaving one end of the outer channel open for the reception of a brush.

A brush 3,5 formed from any suitable material, such as horse-hair, nylon, or the like, is releasably retained between each of the pairs of outwardly presented channel legs 29 with its bristles projecting outwardly beyond the ends of the arms for engagement with a workpiece. A brush 35 is received in each of the channel members 28 by slidably inserting it between the outer pair of channel legs 29 at the open end of the channel. While each pair of arms 12 and 13 normally carries a brush 35, it is contemplated that lin some sanding operations a relatively small number of 'brushes will be employed; in which case not all of the pairs of arms will carry brushes 35. And in still other applications, cloth mats may be substituted for the brushes 35.

Adjacent thebase of Veach of the arms 12 of the spider is aboss 36 integrally formed on the outer face thereof `and provided with an end plate 37 threaded thereon. Axially movable in each boss 36 is a spindle 40 extending through an opening in the end plate 37 and having a knurled handle 42 at its outer end normally abutting the end plate. The opposite vend of the spindle 40 extends 'inward through an opening formed'in the spider 10 and is adapted to engage one end of a spool 46 of an abrasive strip 48. The spindle 40 is biased inwardly by a spring 50 disposed around the spindle between the inner face of `the end plate 37 and a shoulder 51 formed on the spinldle 40.

A corresponding set of spindles 52 are rotatably mounted on the inner face of the spider 11 and cooperate with the spindles 40 for holding opposite ends of the spools 46. The abrasive strips 48 extend outward from their respective spools 46 along the leading faces of the brushes 35 for engagement with a work-piece upon rotation of the heads. A guide bar 54 secured to the leading lface of each of the channel members 28, as by screws 56, positions and retains the strips 48 in close proximity to the leading face of the brush 35 so that during rotation of the head the brushes provide exible support for the ends of the abrasive strips 48 as they are rotated against a workpiece. In most sanding operations, good results are achieved by having the ends of the strips .48 and the lbrushes 35 projectv substantially the same distances beyond the ends of the arms 12 and 13.

In the course of operating the sanding head, Vthe ends of the abrasive strips 48 become worn and breakroi, and it 'is necessary to replace the worn and broken ends with ,fresh lengths of the abrasive strips. In order to feed out fresh lengths of the `strips while the head is rotating, means is provided to drive the spools in a strip feeding direction during such rotation. To this end, a pinion gear 60 is xedly retained on each of the spindles 52 as by a key 62. Conveniently, the keys 62 are of sufficient length to engage the spools 46 to drive them with the spindles 52. The pinion gears 60 mesh with and are driven by a sun gear 64 rotatably mounted on the sleeve 18 and integrally connected by means of an annular web 66 to a worm gear 68 similarly rotatable on said sleeve. Conveniently, the worm and sun gears are axially positioned on the sleeve between the outer end of the spider hub 17 and a snap ring 69,at the inner end of the spacer 21.

The worm gear 68 is in mesh with a worm 70 disposed 'chordally of thespider 11 in a bracket 72 secured to the outer face of the spider 11 by bolts 73. The worm 70 is driven by a ratchet from a lever arm 74 pivoted on the =axis of the worm 70 and extending through an opening :formed in the web of the spider 11. The free end of the lever arm '74 carries a cam follower ball 76 which is received between arpair ofv parallel cam ribs Z8 on the face of a brake drum 80. The brake drum is rotatably received A on the sleeve 18 between the spider 11 and the sleeve flange 19 and is adapted for rotational and counter-rotational movement with respect to the spiders 10 and 11.

Desirably, rotational movement of the drum with respect to the spider is limited by a stop lug 82 mounted on the drum 80 and received in an arcuate slot S4 cut in the web of the spider 11. The drum is biased forward in the direction of rotation of the head by a tension spring S8 stretched between a iixed point on the spider 11 and a bracket 86 on the leg 82 of the drum.

Operation of the sanding head may be described as follows:

The sanding head is positioned on the driving shaft 15 in the manner previously described with the brushes 3S projecting from the arms 12 and 13 and the spools of abrasive secured on the spindles 46 and S2. The strips of abrasive are fed outwardly from the spools between the guide bars 54 and the brushes 35 along the leading faces of the brushes so that the brushes and strips project substantially the same distance from the ends of the arms 12 and 13. Thus, the abrasive strips 48 are supported by the brushes 35 beyond the ends of the arms 12 and 13 so that the strips are kept in contact with a work-piece as the head is rotated in the direction of the arrow A of Fig. 2.

After the head has been in operation for a period of time the ends of the abrasive strips 48 become worn and break ott and fresh lengths of the abrasive material must be unwound from the spools 46. T o feed out fresh abrasive while the head is rotating, a braking force is applied to the drum to retard its rotation with the sanding head and to cause a relative movement between the drum 80 and the spiders 10 and 11. The amount of braking force required is extremely small and can be easily applied by the operator striking the rim of the drum with the heel of his hand. When this braking force is applied to the drum, the drum is thus rotated rearwardly with respect to the forwardly rotating head, the amount of this counter-rotation being limited by the movement of the lug 82 in the slot 84. This relative movement between the drum and the sanding head causes the cam ribs 78 to move the cam follower ball 76 along their length thereby pivoting the lever arm 74 to rotate the worm 70 through a predetermined angle. Rotation of the worm 70 drives the worm gear and sun gear 68 `and 64 on the sleeve 18 in the direction of the arrow B in Fig. 2, and rotates the pinion gears 60 to drive the spindles 52 to feed out predetermined lengths of the abrasive strips 48. When the braking force 1s released from the Vdrum 80, the spring 88 returns the drum to its starting position and positions the lug 82 at `the left of the Vslot v84, as shown in Fig. 3. Movement of the drum Ato its starting position carries the cam follower 'ball 76 outwardly between the cam ribs 78 and the drum 80 is then ready for a new brake actuation.

While I have described Athe operation of feeding out fresh lengths of the abrasive strips when the head is rotating, it is rof course possible to feed out the strips when vthe head is stationary. Such an operation is accomplished by' manually rotating the drum 80 with respect to the spiders to drive the several gears in the manner previously described.

I claim as my invention:

l. A sanding head, comprising a pair of axially spaced end members mountable on a rotatable shaft, means ad jacent the periphery of said end members adapted to releasably lock a plurality of outwardly projecting brushes on said end members, a plurality of pairs of spindles carried on said end members for holding a plurality of spools of abrasive strips, a planetary gear train operatively interconnecting said pairs of vspindles for rotating said spindles with respect to the head to unwind the spools, and means movable with respect to the head for driving said planetary gear train to rotate said spindles when the head is rotating or at rest.

2. Asanding head, comprising a pair of axially spaced end members mountable on a rotatable shaft, means adjacent the periphery of said end members adapted to releasably lock a plurality of outwardly projecting brushes on said end members, a plurality of pairs of spindles carried on said end members for holding a plurality of spools of abrasive strips, one of said spindles in each pair being movable axially of said end members for releasably retaining the spools of abrasive in the head, a planetary gear train operatively interconnecting said pairs of spindles for rotating said spindles with respect to the head to unwind the spools, and means movable with respect to the head for driving said planetary gear train to rotate said spindles when the head is rotating or at rest.

3. A sanding head, comprising a pair of axially spaced end members mountable on a rotatable shaft, means adjacent the periphery of said end members adapted to releasably lock a plurality of outwardly projecting brushes on said end members, a plurality of pairs of spindles carried on said end members for holding a plurality of spools of abrasive strips, a planetary gear train operatively interconnecting said pairs of spindles for rotating said spindles with respect to the head to unwind the spools, a drum movable relative to the sanding head and operatively connected to said planetary gear train for driving said gear train to rotate said spindles when the head is rotating or at rest, and means limiting said relative drum movement for limiting the spool unwinding.

4. A sanding head, comprising a pair of axially spaced concentric spiders having a plurality of radially projecting arms, locking means adjacent the outer ends of said arms adapted for the reception of a plurality of outwardly projecting brushes, a plurality of pairs of spindles on said spiders adjacent the base of said arms for holding a plurality of spools of abrasive strips, a planetary gear train operatively interconnecting said pairs of spindles for rotating said spindles with respect to the head to unwind the spools, and means movable with respect to the head for driving said planetary gear train to rotate said spindles when the head is rotating or at rest.

5. A sanding head, comprising a pair of axially spaced concentric spiders having a plurality of radially projecting arms, locking means adjacent the outer ends of said arms adapted for the reception of a plurality of outwardly projecting brushes, a plurality of pairs of spindles on said spiders adjacent the base of said arms for holding a plurality of spools of abrasive strips, a guide bar adjacent the end of each of said arms for disposing the abrasive strips adjacent the brushes, a planetary gear train operatively interconnecting said pairs of spindles for rotating said spindles with respect to the head to unwind the spools,` and means movable with respect to the head for driving said planetary gear train to rotate said spindles when the head is rotating or at rest.

6. A sanding head, comprising a pair of axially spaced concentric spiders having a plurality of radially projecting arms, a plurality of axially extending channels interconnecting the spiders adjacent the outer ends of said arms and adapted for the reception of a plurality of outwardly projecting brushes, a plurality of pairs of spindles on said spiders adjacent the base of said arms for holding a plurality of spools of abrasive strips, a planetary gear train operatively interconnecting said pairs of spindles for rotating said spindles with respect to the head to unwind the spools, and means movable with respect to the head for driving said planetary gear train to rotate said spindles when the head is rotating or at rest.

7. A sanding head as set forth in claim 6 in which said channels are pivotally adjustable on said arms for adjusting the angle of projection of said brushes.

8. A sanding head, comprising a pair of axially spaced spiders mountable on a rotatable shaft, means adjacent the periphery of said spiders adapted for releasably locking a plurality of outwardly projecting brushes on said spiders, a plurality of pairs of spindles carried on said spiders for holding a plurality of spools of abrasive strips, a pinion gear on each of said pairs of spindles meshing with a sun gear normally rotatable with the head,and means normally rotatable with the head for rotating said sun gear with respect to the head to rotate said spindles for unwinding the spools thereon.

9. A sanding head, comprising a pair of axially spaced spiders mountable on a rotatable shaft, means adjacent the periphery of said spiders adapted for releasably locking a plurality of outwardly projecting brushes on said spiders, a plurality of pairs of spindles carried on said spiders for holding a plurality of spools of abrasive strips, a pinion gear on each of said pairs of spindles meshing with a sun gear normally rotatable with the head, and means for counter-rotating said sun gear and head for rotating said spindles with respect to the head to unwind the spools thereon.

10. A sanding head, comprising a pair of axially spaced spiders mountable on a rotatable shaft, means interconnecting said spiders and adapted for the reception of a plurality of outwardly projecting brushes, a plurality of pairs of spindles on said spiders for holding spools of abrasive strips in the head, a pinion gear on each of said pairs of spindles meshing with a sun gear, said pinion and sun gears being rotatable with respect to the head to unwind said spools of abrasive by a worm gear connected to said sun gear and driven by a worm mounted on one of said spiders, and a drum operatively connected to said worm and movable with respect to the head for actuating said worm to unwind said spools.

l1. A sanding head, comprising a pair of axially spaced spiders mountable on a rotatable shaft, means inter connecting said spiders and adapted for the reception of a plurality of outwardly projecting brushes, a plurality of pairs of spindles on said spiders for holding spools of abrasive strips in the head, a pinion gear on each of said pairs of spindles meshing with a sun gear, said pinion and sun gears being rotatable with respect to the head to unwind said spools of abrasive by a worm gear connected to said sun gear and driven yby a worm mounted on one vof said spiders, and a drum movable with respect to the head having cammng means engaging a lever arm on said worm for driving said worm to unwind said spools during movement of the drum with respect to the head.

12. A sanding head as set forth in claim 1l in which said lever arm is provided with a ratchet for driving said worm only during movement of the drum with respect to the head.

13. A sanding head, comprising a pair of axially spaced spiders mountable on a rotatable shaft, means interconnecting said spiders and adapted for the reception of a plurality of outwardly projecting brushes, a plurality of pairs of spindles on said spiders for holding spools of abrasive strips in the head, a pinion gear on each of said pairs of spindles meshing with a sun gear, said pinion and n sun gears being rotatable with respect to the head to unwind said spools of abrasive by a worm gear connected to said sun gear and driven -by a worm mounted on one of said spiders, a drum movable with respect to the head having camming means engaging a lever arm on said worm to unwind said spools during movement of the drum with respect to the head, and stop means interconnecting said drum and of one of said spiders for limiting the relative movement of the drum and the head to limit the spool unwinding.

14. A sanding head as set forth in claim 13 in which said stop means is provided with tension means urging said drum into normal rotational movement with the head.

15. A sanding head, comprising a pair rof axially spaced members mountable on a rotatable shaft, means on each of said members adapted to releasably lock a plurality of outwardly projecting brushes thereon, a plurality of pairs of spindles on said members for holding a plurality of spools of abrasive strips, and a drum rotatable with respect to the head and operatively connected to said spindles through a plurality of intermeshing gears for 919,054 retating said spindles to unwind the spools of abrasive 1,949,565 when the drum is rotated with respect tn the head. 2,709,323

References Cited in the flle of this patent 5 UNITED STATES PATENTS 564,587 Black July 28, 1896 Milne Apr. 20, '1909 Edwards Mar. .6, 1934 Swan May l31, i955 Monjar July 19, 17955

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