US2224132A - Mechanical file - Google Patents

Description

R. BARNES MECHANICAL FILE Original Filed Dec. 4, 1936 2 Sheets-Sheet l Um max R. BARNES MECHANICAL FILE Original Filed Dec. 4, 1936 2 Sheets-Sheet 2 IN VEN TOR. ,Vlf'was.

Patented Dec. 10, 1940 PATENT OFFICE MECHANICALFILE Robert Barnes, San Francisco, Calif, assignor to Guy E. Russell, San Francisco, Calif.

Application December 4, 1936, Serial No. 114,236 Renewed February 26, 1940 4 Claims.

The present invention relates to improvements in a mechanical file and has reference generally to abrading, smoothing and polishing tools.

Where considerable filing and polishing is to be done, as in the preparation of the surfaces of an automobile prior to the application of surface coatings, it is customary, at thepresent time, to provide a suitable, hand-operated carrier, to the bottom face of which the file is attached and which is manipulated by pushing the same back and forth over the surface to be treated.

In the present invention it is proposed to substitute power-operated for hand-operated means and to provide power-operated means in the carrierfor rapidly reciprocating the file so that the operator is relieved of the burdenand may devote his entire attention to the holding and guiding of the carrier. This power-operation has the further advantage of allowing of much quicker reciprocation than is possible where manual power is relied on.

It is furtherproposed to provide means in connection with this invention whereby the speed of reciprocation may be adjusted.

5 It is further proposed to provide means for adjusting the length of stroke of the reciprocating file.

It is further proposed to ,use compressed air as the driving means for my mechanical file and to provide control means positioned for convenient operation by the hand of the operator holding the tool.

It is still further proposed to provide a novel lubricating means for the moving parts of my inventi'on whereby a lubricant is entrained in the compressed air used as the driving means.

It is further proposed to provide means Whereby the air exhausted from the device may be used to clean and cool the surface on which the file works.

And finally, it is proposed to combine all the features outlined into a compact structure, which is comparatively simple in construction, durable in operation and easy to handle.

Further objects and advantages of my invention will appear as the specification proceeds.

The preferred form of my invention is illustrated in the accompanying drawings, in which:

Figure 1 shows a side view of my mechanical file,

Figure 2 a top plan view thereof,

Figure 3 a central, vertical, longitudinal section through the device,

Figure 4 a transverse vertical section taken 55 along line 4-4 of Figure 3,

Figures 5 and 6 schematic detail views explaining the valve operation.

While I have shown only the preferred form of my invention I wish to have it understood that various changes or modifications may be made 5 within the scope of the claims hereto attached Without departing from the spirit of the invention. More particularly I Wish to have it understood that while I described the tool as a mechanical file it may be readily used for any 10 smoothing, polishing and sanding operation by substituting any desired abrasive surface for that shown in the drawings.

Referring to the drawings in detail, my mev chanical file I comprises an elongated housing 2 15 comparable in general outlines to the conventional Wooden plane and having a handle 3 at the rear end and a gripping member 4 attached over the front end, so that it may be conveniently manipulated by grasping the handle with one 20 handv and the gripping member with the other hand.

The housing is cored from opposite ends to provide two longitudinal cylinders I4 separated by a central partition I5 which latter is cored '25 from one side to provide a valve chamber 16 (see Figure 4) between the two cylinders. Each of the cylinders has a piston l'l reciprocable therein and the two pistons are interconnected, by means 7 V of a slide l8 riding on the underface of the hous- 0 ing, the slide being secured to the outer ends of the pistons as at l9 and the cylinder walls having slots 20 to permit the connections-2| between the pistons and the slide to travel therein.

The pistons are reciprocated by means of com- 35 pressed air in the following manner: A nipple 22 arranged above the handle 3' is connected to a source of supply and leads the compressed air, through a tube 23, to aradial port 24 in the plug 25 used for closing the outer end ofv one of the i0 cylinders, and the radial port connects with an axial port 26 leading to a small chamber 21 formed upon the outer end of the plug by means of a diaphragm 28.

A stud 29 projecting from the outer face of 45 the diaphragm is connected to one end of a curvedlever 3B pivoted to the handle as at 3| and pressed upon by the spring 32 which tends to close the port 26. The free end of the lever 30 is arranged in substantially parallel relation to the gripping portion of the handle 3 and so as to slightly project therefrom, which permits the operator to open the port 26 by a slight pressure of his fingers upon the lever. When the port 26 isopened in this manner, compressed air enters the chamber 2! and passes through conduits 33, 34, and 35 into the valve chamber IS in the central partition.

The valve chamber I6 is closed by means of a plug 36 and the valve itself comprises a disc 31 bearing upon the inner end of the valve chamber and having a shaft 38 projecting through the plug 36, while a spring 39 urges the valve upon its seat. The inner ends of the two cylinders 4 are connected to the inner wall of the valve chamber by means of two ports 40 and 4| arranged in spaced relation to one another and the valve disc 31 is formed with a port 42 which is made to register with one or the other of the two ports 40 and 4| as the disc is made to move from one position to another. The means for effecting this valve movement will be discussedlater.

The valve disc 31 is also formed with two radial grooves 43 and 44, on opposite sides of the port 42 and these grooves are positioned so that when the port 42 registers with one of the ports 40, 4|, the outer end of one of the grooves communicates with the other port and connects the same to the exhaust passage 45 in the housing so that when one of the cylinders receives the pressure medium, the other one exhausts and vice versa.

The exhaust conduit is controlled by a threaded plug 45 which is operated by means of a disc 4'! engaging the squared end of the plug and held to the housing by the holder 48 screwed to the housing as at 49. The holder has an aperture 50 through which the disc appears and the latter is suitably graduated for comparison with a mark 5| on the holder so that the disc may be set to any desired position.

It is apparent that the port area of the exhaust determines the speed at which compressed air may be passed through the device and that therefore the piston speed may be controlled by the proper setting of the disc 41, which latter is preferably marked Speed control (see Figure 2). As the size of the exhaust port is decreased, the length of time required to com- 45 pletely exhaust the cylinders is increased correspondingly.

The exhaust conduit is continued beyond the plug to pass downward as at 52 (see Figure 4), and to discharge toward the surface worked on by the tool for cleaning and cooling the latter surface.

The valve disc 31 is operated as follows:

The outer end of the shaft 38 has a crank arm 53 which is connected, through a spring 54, with the long arm of a lever 55 pivoted as at 56 in such a manner that the two connected ends swing on opposite curves so that, when the crank arm occupies one operative position and the lever arm is swung in the opposite direction the spring causes the crank arm to follow with a snap action, since the spring is made to expand and contract during the movement. Suitable stops 51 are provided to limit the valve movement.

The lever 55 is actuated, that is, swung in one,

direction or the other at the end of each piston movement, by means of two shoes 58 and 59 arranged in an elongated slot 6|] in the slide l8 on opposite sides of the lower arm 6| of the lever 55. The two shoes are mounted on opposite threads of a rod 6| supported in the slide and held against endwise motion by a screw 62 riding in a registering annular groove in the rod.

The rod may be turned by any suitable tool engaging the squared end 63 thereof and the spacing between the shoes may thus be adjusted.

One of the shoes strikes the lever 55 at the end of each piston movement for effecting a reversal of the valve 3'! and it is apparent that the spacing between the shoes controls the length of the piston stroke 50 that the latter may be changed as desired by adjusting the spacing between the shoes.

The main slot of the slide, in which the two shoes are adapted to move, is extended laterally to the edge of the slide as shown at 69 and at least one of the shoes has a thin lateral extension 10 projecting through the slot so as to be visible from the outside for reading with a scale placed on the outside of the housing adjacent the slot so that the spacing between the shoes may be ascertained from the outside.

The pistons I! have particular lubricating feature insofar as they are formed with pockets 12 facing the compression chambers, each pocket being filled with felt 13 or other absorbent material, and the felt being saturated witha lubricant. The open end of the pocket 'is closed by means of a perforated cap 14, which allows a portion of the compressed air to enter the pocket and to entrain a slight amount of the lubricant, whereby all the working faces contacted by the air are continuously lubricated. New lubricant may be admitted to each piston from the outer end, as shown at T5.

The front end of the front cylinder may be suitably closed by a removable front wall I6 and the valve operating mechanism may be covered by a plate 11.

The slide I8 is formed with suitable mounting means for the file l3 which may comprise two spaced, undercut elements 54 and 35 adapted to receive the file between the same, the file being formed with beveled end edges 66 fitting into the undercuts. The element is preferably made adjustable by being dovetailed into the slide as at 6! (see Figure 3), and may be tightened upon the file by the screw 68.

The operation of my device will be readily understood from the foregoing description and particularly from the diagrammatic views of Figures 5 and 6. Figure 5 shows the valve mechanism substantially in the position of Figure 3, in which the shoe 59 has struck the lower end of the lever 55 and has thereby effected a change in the valve position so that compressed air passes through the conduits 34 and 35 into the valve chamber I6 and thence through port 42 in the disc 31 and the port 4| in the partition and into the right-hand cylinder of Figure .3, while the air from the left-hand cylinder is exhausted through the port 40, the groove 43 in the valve disc 31 and the exhaust port 45.

The two pistons will now move to the right (see Figure 3) until the second shoe 58 strikes the lower end of the lever and reverses the parts as shown in Figure 6. The spring 54 has been omitted from the diagrammatic showing for the purpose of clarity, but it is apparent that as the upper end of thelever is swung from right to left, the crank arm follows the movement with a snap action due to the expansion and contraction of the spring.

In the new position the conduits 34, 35 connect with the valve chamber, as before, but the compressed air is admitted into the left-hand cylinder through the valve port 42 in the disc 31 and the partition port 40, while the right hand cylinder is connected to the exhaust through the partition port 4|, the valve groove 44 and the port 45,,

whereby a reversal of the piston movement is effected.

The admission of the air is controlled by the hand lever 30. The piston stroke may be adjusted by positioning the shoes 58 and 59 and the piston speed may be controlled by adjustment of the plug 46 in the exhaust passage.

I claim:

1. In a tool of the character described, a housing having a pair of alined cylinders therein and a partition interposed between the cylinders, a pair of pistons spaced apart and reciprocable in the cylinders, means for introducing pressure means into the cylinders between the partition and the inner faces of the pistons for reciprocating the latter, a valve control for the pressure means mounted in the partition between the pistons, the valve control having means associated therewith for exhausting one cylinder when pressure means is being introduced into the other cylinder, a tool holder having means for securing a tool thereto and being reciprocable upon the outside of the housing in parallel relation to the piston movement, the housing having slots therein, and means slidable in the slots for connecting the pistons to the tool holder for transmitting reciprocating motion to the latter.

2. In a tool of the character described, a housing having a pair of alined cylinders therein and a partition interposed between the cylinders, a pair of pistons spaced apart and reciprocable in the cylinders, means for introducing pressure means into the cylinders between the partition and the inner faces of the pistons for reciprocating the latter, a valve control for the pressure means mounted in the partition between the pistons, the valve control having means associated therewith for exhausting one cylinder when pressure means is being introduced into the other cylinder, a tool holder having means for securing a tool thereto and being reciprocable upon the outside of the housing in parallel relation to the piston movement, the housing having slots therein, and means slidable in the slots for connecting the pistons to the tool holder for transmitting reciprocating motion to the latter, the sliding tool holder having means thereon for operating the valve control.

3. In a tool of the character described, a housing having a pair of alined cylinders therein, a

' pair of pistons reciprocable in the cylinders,

means for introducing pressure means into the cylinders active on the inner faces of the pistons for reciprocating the latter, a valve control for the pressure means mounted between the pistons, a member reciprocable upon the outside of the housing in parallel relation to the piston movement, the housing having slots therein, and means slidable in the slots for connecting the outer ends of the pistons to the said member for transmitting reciprocating motion to the latter, the sliding means having means thereon for operating the valve control and the latter means being adjustable for adjusting the stroke of the piston.

4. In a tool of the character described, a manipulating means for a rotary valve comprising a crank arm operating the valve, a lever mounted in confronting relation to the arm and eccentrically relative thereto, means for engaging one end of the lever for alternately thrusting the same in opposite directions and a spring connection between the end of the arm and the other end of the lever, the latter two ends being made to swing on opposite curves.

ROBERT BARNES.

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