US1717999A - Pneumatic or like tool - Google Patents

Description

June 18,1929, s. D. OLSEQ'N 1.71%99 PNEUMAEIC OR' LIKE TOOL Filed Nov. 22, 1923 5 Sheets-Sheet 1 June' 18, 1929. S. D, OLSEN 1.737.999

PNEUMATIC OR LIKE TOOL Filed Nov. 22, 1923 5 Sheets-Shet 2.

Jaw/fir film/020% fire/0 {7 ifhzywy June 18, 1929. s. DTDLSEN 1,717,999

PNEUMATIC OR LIKE TOOL Filed Nov. 22, 1923 3 Sheets-Sheet 3 Patented June 18, 1929.

UNITED STATES PATENT OFFICE.

SIMON DOKK OLSEN, OF ALBANY WHARF, LONDON, ENGLAND, ASSIGNOR TO THE OL$EN ENGINE SYNDICATE LIMITED, OF ALBANY WHARF, LONDON, ENGLAND, A-

BRITISH COMPANY.

PNEUMATIC OR LIKE TOOL.

Application filed November 22, 1923, Serial No. 676,311, and in Great Britain November 27, 1922.

This invention has reference to rotary pneumatic drills or like tools and relates more particularly to an improved construction of rotary or boring tool or drill designed to work with little or no vibration and to be more compact and efficient than ordinary pneumatic tools.

According to the invention the tool is driven by an engine comprising a cylindrical cam or Vshaped drum mounted on a shaft or spindle, the opposite edges thereof being acted on by rollers carried by opposed sets of pistons, each set of pistons belonging to a group of cylinders at opposite sides of the cam. The edges of the cam and roller are bevelled to ensure smooth running and a two-speed or other gear is provided to give a driving connection between the cam and the tool-shaft.

The latter is provided with a thrust-block having ball or roller bearings, and the engine is supplied with compressed air or other working fluid by a rotary-valve arrangement.

The whole is enclosed in a casing having a screw-cap or cover at its rear end, which can be placed against the body when the tool is to be used as a breast-drill for instance. A pointed stud may also be fixed in the centre of this cap, to act as a rear pivot if the tool is to be fitted in a yoke or frame, in which case the screw-cap acts as a feed screw.

In order that the invention may be clearly understood and readily carried into effect, reference will now be had to the accompanying drawings, in which Fig. 1 is a longitudinal section of one example of the improved pneumatic tool constructed as a drill.

Fig. 1 shows one of the handles which is broken away in Fig. 1.

Fig. 1 is a detail view showing the rear stud or pivot.

Fig. 2 is a front view of the tool partly in section but placed so that the handles are horizontal.

Fig. 3 is a transverse section on the line 33 of Fig. 1.

Fig. 1 is a development of one of the rotary valves hereinafter referred to, and

Fig. 5 is a plan of one of the pistons.

Fig. 6 is a longitudinal section of the variable or change-speed gear corresponding to that shown in Fig. 1, but shifted slightly to the right to give a direct drive to the tool.

Fig. 7 is a fragmentary detail plan view showing an inclined or cam-like groove and a knob or handle for shifting the speed gear.

Fig. 8 is a diagrammatic view in section on the line 88 of Fig. 7 showing the gears out of mesh when the drive is direct as in Fig. 6.

Fig. 9 is a corresponding view showing the gears meshing together, as in Fig. 1, when the tool is driven through them instead of direct.

In this example, a is the casing of the tool which comprises a light steel tube or shell, say about four or five inches in diameter with two castings a fittedone in each end. These castings are provided with bushings b to form bearings for the tubular or hollow main shaft 5 of the cam c, which serves instead of a crank for giving the rotary motion. The said castings also serve as the engine frame and have formed in them the working cylinders (Z, of which in this case there are five in each casting, the corresponding cylinders at opposite ends being in axial alignment.

These cylinders are about an inch in diameter and their pistons e are hollow and formed of light metal such as duralumin or thin sheet steel. They have bushings or brass pieces 6 fitted inside them to serve as bearings. These carry cross-spindles e for the rollers f which act on the opposite edges of the cam 0, and so set up the rotation of the latter and of the shaft 6, said shaft being coaxial with the cylinder groups.

The edges of the cam and rollers are bevelled as at e to ensure proper running.

The bearings 6 may be in the form of square cups and be kept in place by pins 0 which engage them transversely the ends being secured in the pistons. To prevent undue wear or thrust, the end of each crossspindle e where it presses against the end wall of the outer bearing 6 may rest against a steel ball 6 to take up the thrust Without friction.

The driving cam 0 consists of a cylindrical piece, shell or drum, with a central web 0 like a belt-pulley for instance. The widest and narrowest parts of this cam drum (see Fig. 1) lie diametrically opposite one another its web being thickened at one side to secure proper balance in running.

Hence it is approximately V.-shaped, the cam tracks formed by its side edges 0 being tapered equally but in opposite directions.

distributing working The thrusts of the pistons e and rollers f on these opposite edges therefore counterbalance each other, the cam being nipped between the rollers and thus having a rotary motion imparted to it, without setting up any cndwise strains. A key 0" serves to form a driving connection between the main cam c an d the shaft 6.

The months of the cylinders and pistons are recessed or slotted as at g and 9 respectively, to allow them to overlap the cam, thus considerably reducing the length of the tool, and allowing each side of the cam to project well into the cylinders without interfering with its rotation.

he shaft Z) on which the cam c is mounted, is formed by a hollow spindle or sleeve which is [itted in bearings t and surrounds the tool spindle Z The said tabular shaft also carries at its opposite ends two rotary sleeve valves i for fluid to the cylinders as hereinafter explained, and has a conical bearing 2 at one end which serves to keep the adjacent valve in position, the other being held in place by a fiat end ring 6*.

That end of the main shaft 6 near the tool is provided with a pinion it having teeth 71, to cooperate with a variable-speed gear 71, h h in a cover a at the front end of the casing, adapted for instance to permit either a direct drive between the cam shaft or main spindle 7) and. the tool spindle (F) or to allow them to be geared together in some pre-arranged ratio. One of these gears, viz 71; has a set of internal teeth ]L5 which (as will now be described) can be put into mesh with the teeth. 7L1 to give a direct drive, when the two other gears 7L2 7L3 are disengaged.

These two gear wheels if h are carried 011 a spindle h having an eccentric mounting in rotatable blocks or bearings These bearin gs can be rotated by a knob or lever 70 working in an inclined slot or cam groove is in the lasing (IF. Hence the knob 70 when operated will give the mountings 70 not only a partial turn but also an endwise movement. The former action will draw back and disengage the teeth of [L2 h from 7L1 and h owing to the eccentricity, whilst the latter action will engage the internal teeth h with the ends of the teeth 7L1 and so give the direct drive, and vice versa. 7

To communicate the above endwise move ment to the gears concerned without interfering with the rotation, one of the mountings 70 has a wide disc or flange 70 whose edge engages a groove 73 in the hub of the wheel 7L Also a gap a is left in the casing a and a recess 7) is made in the bearing cone L to give clearance for the parts to move endwise.

As shown in Figs. 1 and 9 the train of teeth 71, [L2 71, if are all in gear with each other, and the hollow main shaft 6 drives the tool-holder socket 1 at a reduced speed, the knob 70 being turned over to the extreme left (Fig. 9) On the other hand, when the knob is moved half way over towards the right, that is to say along the straight half of the groove I? it turns the eccentric axle 70 and thus causes the two pairs of gears to move apart radially, so that the teeth h no longer drive the others and the tool remains at rest. At this time the knob will of course, be standing upright. When the knob is turned completely over (See Figs; 6, 7 and 8) it traverses the inclined. or cam-like part of the groove 7.? and so pushes the spindle 1 1, and the sliding gears all sidewise so that the internal teeth a enter between the teeth 72, and the latter thus drive the tool holder direct at the same speed. as the main shaft Z). Meanwhile the eccentric axle 7&1 has moved further round (along with the knob) and increased the clearance between. the disengaged gears to the full extent shown in Fig. 8.

Z is a tapered socket forming the tool holder, the end-thrust of which. is'taken by a ball. bearing Z fitted against a flange (1, inside the casing, said flange having oil-holes The tool-holder Z is formed in one with the long hollow stem or shank Z which extends hack into the main shaft 7). The body of this stem is smaller than the shaft, but its rear end is slightly enlarged to lit the same and form a hearing as at Z.

The mouth of the tool-holder may be supported in a screw collar Z and be shaped to take standard forms of drills. In the example shown it is slightly tapered to take a tapered tool stem Z and it has a rectangular axial recess l to receive a central block or tongue piece Z on the tool stem.

at is the end-caper screw-cover by which the rear of the tool is enclosed. It is made smooth and only slightly dome-shaped so that the operator can press against it when using the device as a breast-drill.

This end cap is provided with cogs m around its edge to en able it to be easily turned, and has a small central socket or cavity m in which the stud m, Fig. l can be. inserted to form a centre-pin when the device is fitted in a frame.

n is a pusher rod which is used to free the tool if the same should be found to have stuck in the socket Z when it is to be removed.

It has a collar a mounted. on it to steady it inside the hollow stein Z and prevent it falling out when the tool is used upright. Its rear end abuts against the small socket 922?, whilst the forward end (when the drill in position) abntsagainst the central. pin of the tool stem in the recess or cavity Z".

To disengage the tool, the cap on is screwed up a little which forces the rod 11, and with it the tool itself a little forward, and so frees the latter.

At the opposite sides of the casing a are iii fitted two handles 0 and p. These are carried by short hollow stems 0 and p which extend through the casing, being flanged on the inner side thereof, and clamped in position by nuts and p and washers 0 and 2 The handle 0 forms a sleeve which can be rotated half-aturn on its tapered stem 0 by the operator without releasing it, and acts as a valve for controlling the admission of compressed air or other working fluid which i s supplied by a flexible pipe screwed to a nipple 0* on a screwcap 0. This'cap screws on to the step 0 and abuts against a. spring *asher 0 which latter presses the handle 0 onto its tapered stem 0 to preserve an air-tight joint. The air to operate the tool passes down a central passage Q to a transverse passage with which co-operatcs a port inside the handle 0, controlling two other passages g" and 9 hen the parts are in the position shown in Fig. 2, air can therefore pass from g to whereas if the operator gives the h andle 0 a half turn on its stem 0 the port 1} will be carried over to the other side and. the air will then be admitted to the passage (1. In this way, as explained in detail. a little further on. the operator can reverse the direction of the drill simply by a half turn of the handle without having to let go of the handle 0. Moreover by giving the handle 0 only a quarter turn, the port f is put out of register with the other passages, the air supply is shut off and the tool is stopped.

Any suitable click device, such as a spring-- pressed. hall 0 engaging one or other of three holes or notches in the stem 0 may be provided to indicate the three positions, so that the operator can feel when he has turned the handle suliiciently.

The edge of the handle 0 is also cut away as at 0 and a pin or stop '0" is provided to limit the movement positively in the two extreme positions.

The outlet of the exhaust air or fluid takes place through a passage p in the stem p ot the opposite handle p. A rotatable shield or guide 12 wh ich can be clamped by a screw cap 9) and has one or .more openings 1) in one side is provided to direct the exhaust away from the operator.

It will be seen that the pipes for the inlet and outlet of the air or other working fluid are arranged in the middle of the tool, approximately opposite the centre or web of the cam c.

The iii-flowing air is led from the handle 0 by a separate pair of pipes or passages and g, in opposite directions to each of the two rotary valves i which distribute it to the respective. groups of small cylinders cZ around the central shaft.

To permit of this the passages in the handle 0 extend side by side through the stem of said handle into the casing a, and from each, the corresponding passages or 9 lead (see Fig. 1) in opposite directions to the two rotary valves 2'. One of each of the passages 1, g is shown in Fig. 1 in full lines, 1' spectively on the left and the right, for the sake of clearness. As however (see Fig. these pas sages are not exactly central, it will be understood that the passages g (which are supplied with air through Q3) actually lie a little behind the general plane of Fig. l, whilst the passages g are slightly in front of it, and are supplied through the other passage g in the handle.

Each of the rotary valves 2' has two annular grooves or ports 2' 2' corresponding with Q5 and g, and each communicating with a central distribution port of which there are two in each valve. From one or other of these ports 6 (according to the position of the handle valve 0) air can enter a port (Z and pass into the cylinder by a gap or recess 6 in the rear of the piston c. This groove. is simply used to economize space by enabling the engine to be shortened a little.

The cylinders may be arranged to exhaust through the inner ends of the aforesaid slots 9 for accommodating the cam, when these ends are uncovered by the piston.

The pistons 6 may be steadied and prevented from turning by projections 0 working in slots 9 or in grooves in the cylinder walls. They may be cushioned in the backward or return stroke, so that they are always under a pressure which tends to keep the rollers f steady against the cam edges and so prevent chattering or knocking.

It will be seen that each rotary valve 2' is concentric with the shaft 6 but a slight gap or annular space is left between them to intercept vibration. The driving connection is set up by a pin or key 2' projecting into a slot in the shaft.

Between the cylinders, the end castings or cylinder frames a are tied together longitudinally by steel rods 1" parallel with the shafts, which rods take up the counter strains of the opposing pistons, the shell a forming a distance piece as it were.

Obviously the above arrangements may be modified in various ways in carrying the invention into practice Without departing from the general nature thereof.

I claim 1. In a rotary pneumatic drill or like tool, the combination of a tool-holder, a cylindrical cam two groups of cylinders disposed at opposite edges of said cam, a tool-spindle coaxial with said cam, a rotary sleeve valve for controlling each group of said cylinders, a rotatable handle at one side of the tool forming an inlet valve, and a corresponding handle at the opposite side forming an exhaust valve, substantially as described.

2. In a rotary pneumatic drill or like tool, the combination of a tool-holder, a cylindrical cam having tapered sides, a hollow camshatt, a tool-holder spindle inside said shaft, two-speed change-speed gear for driving said spindle from said shaft and for putting it out of gear, two opposed groups of cylinders and pistons acting on said cam, and a rotary sleeve valve co-axial with the camshaft for controlling each of said groups, suhstai'itially as described.

3. In a rotary pneumatic drill or like tool, the combination of a cylindrical can'i with oppositely inclined sides, a hollow cam-shalt, a hollow tool holder spindle, changespeed gear for connecting and disconnecting said shaft and spindle, opposed groups of cylinders and pistons for operating said earn, a rotary sleeve valve co-axial With the cam-shaft for controlling each group of cylinders, handles at opposite sides or the tool, a rotary sleeve on one handle provided with valveports, and passages from said ports to each of said rotary valves, substantially as described.

In. testimony whereof I atlix my signature.

SIMON DOKK OLSEN.

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