US2740406A

US2740406A - Pneumatic cutting tool

Info

Publication number: US2740406A
Application number: US445523A
Authority: US
Inventors: Benjamin F Tofflemire
Original assignee: Individual
Current assignee: Individual
Priority date: 1954-07-26
Filing date: 1954-07-26
Publication date: 1956-04-03
Anticipated expiration: 1973-04-03

Description

April 3,1956 5. F. TOFFLEMIRE 2,740,406

PNEUMATIC CUTTING TOOL Filed July 26, 1954 2 Sheets-Sheet l L o L U I 1 INVENTOR BENJAMIN F-TOFFLEM1RE y ATTORNEYS T 5 +6 12 F 16 23 P N l 1 I) 25 April 3, 1956 B. F. TOFFLEMIRE 2,740,406

PNEUMATIC CUTTING TOOL Filed July 26, 1954 2 Sheets-Sheet 2 AT TORNEYS United States Patent PNEUMATIC CUTTING TOOL Benjamin F. Tofliemire; Lafayette, Calif. Application-July 26; 1954, Serial No, 445523 Claims. (Cl. 128-310) in thoseinaccessible and difiicult-to-reachareas found in impaction-work in eXodontia and; bone-surgery, as well astheconstricted areasin industry. Heretofore, hammer-andchisel work' in these constricted areas-made many of 'these operations not only verydifii'cultto perform; but"'the:'use of the chisel wasinefficienfandfim efiectivez- 'Ifhe lightness of the instrument 'permits'the surgeon'to continue'his intricate work without tiringor beingplaced under a nervous strain; Alsothe 'compactncss 'ofth'e instrument reduces the apprehensiona nd nervousness-of the patient in case the operation is-do'ne' under a local anesthetic.

Another novel feature lies in the adaptation of carbon dioxide gas underpressure-for the operationof the device instead' of by compressed air or any other'compressed gas. Carbon dioxide can be storedin'pprtable containers and used for operating the tool 'when' needed. This not only obviates the necessity of having=an-aircompressor available;but also eliminates the use-ofnonsterile; water-vaponladen air in the operative new where the tool is being used. Theelimination"of the watervapordziden air, moreover; further'protectsmnw of the accessory equipment, such' as-cutters;- gouges, elevators, etc: from rust' andicorrosion. v

A novel exhaust control mechanism-of this instrument,

diverts and conducts the airor gas used 'to-operate th'e device, away--'from th'eoperating-fielm thereby -ahsolutely preventing any'possible contamination=- of"the operative field! This feature isveryessentialito a su'r-geona- The instrument 'is-made throughout of "stainless steel and so designed as to permit sterilization of the entire instrument. The corrosion resistantproperties of the-deviee assures ithaving ta long life and freedorn from "rust-and othercorrosion induced contaminants.

A toot-pedal control of the instrument= permits the operator to concentrate on precision guidance of the instrument' without the distracting; lossof control and Wavei'ing -oc'casioned-by the-- grip=changenecessitated by a hand-operated control valve.

The-Icomplete portabili'ty"of the instrument and the compressed car-bondioxide gas; permits the surgeon-to carry the equipment with him on emergency calls'gor OPEIHtEilHlthB home :orein ssmall'er rhospitals: not e quipped safe compress'or: service: Likewise, .the trouble.- shooter -"ine.industries; may CHYIYFthQi equipmentr; to sthe scene @ff-the troubles-and .permitr-him: to: reachethosercon- 2 stricted areas'with an eflicient; rapid, andlfully controlled device.-

Various cutting instruments such as trimmers, gouges, chisels, rougeurs, and planes, are allreadily interchangeable and*are:so-designed as to be inserted orremoved with the minimum time; etfort and confusion.

Otherobjects and advantageswill appearin the following specification, andthe novelfeatures'of the device will beparticularly pointed outin the appendedclaimsr,

My invention is illustrated in the accompanying drawingsforming a part 'of this application; in which:

Figure- 1-is"a-view ofthe tool shown operatively connectedto a tank of compressed gas;

Figure 2 is an enlarged-elevational'view of the, tool;

Figure 3 is an enlarged longitudinal section taken along thdlihelIP-III of Figure 1 and'illustrates the pneumatically operated parts in intake position;

Figure 4'isalongitudinal "section taken along, the line IV-'-IVbfFigure-3 andshows the pneumaticallyoperated parts'in exhaust position;

Figure 5' is a longitudinal section taken through the cylinderand'sh'ows" the piston in elevation and in; the same position *as in Figure 3;

Figure is a transverse section taken along the line VI -V1 of-Figure 5 and illustrates the cylinder;

Figure 7 is aplan view of a disc that closes-the lower endlzofthe cylinder; and the view istaken'wh'enlookin'g in the direction of thearrows VIl,-VII of'Fig'ureS; and

Figure '8 is"an elevationalview of"the,inlet tube and associate parts.-

while I have shown onlythe preferred 'forrrr'of 'my invention; it shoulwbe understoodfthat various changes ormrodifieat-ions may-'bemadewithinithescope of the appended claims without departing from the, spirit. and scope of the-invention. V

In carrying out myinvention I *will'gdescrihe the structural *p arts as= shownrin Figures to 8;,inclusiv'e; and then will set forth how the tool; can the connecteditoza' -tankof*compress ed"g as, such-as carbon: dioxide." Itis bestfiist td refer" to "Figure 5 "wherein I show thecylinder as -having-arcylindrical bore lin: which a piston 'Bis reciprocably mounted. Itwill be noted that the ;upper thanthe lower portion- 11) of'th'e same here 'and'that the cylinder, is-providedwith an annular groove 2" at; the juncture of thecylindricalbore' portions 1:: and 111; [The piston h'as; an upper reducedportionfi 1 which, is of the same-diameter asthe' cylindrical bore portion l'a 'an d has a -ldwer*larger portion' 4of a diameter-that is the same as the diameter -of' the -'lower'cylindric'a1 portion'db. Then-piston B is freeto*slide within-the b'ore lof the cylinder-mvi-thin certainzlimits. A' Ishoulder 5t-is formed on: the pis'tomrBi at.:the sjunctureyof'i thei portioni 3!.with therpor ionA-w I provide-the pistonsB with anwaxialwair passager6 that-\extendsfrom athe; bottom- 7 of the-pistont-upwardly tosaapoint inatheereducedspprtion S -Where-Ythe top of the.air,.. ducbeommunicates with. at diametrically extend ing air passage,.8, -whose ends terminate: at theaouter surface of the cylindricalportiondt When the pistonsB is. in, intake position, the air passage 8 will -havefit's, ends both'intcommunication with the annular air, passage 2. ThecyliiiderA has'a'bl'eed opening 9'near its top that communicates with the upper boreportion 1a, seeFi'gure 5} and the -cylinder also has diametrically; opposed exhau'sh ports 10, see Figure-4 thatareplaced inthe lower bore porti'on 1b of the cylinders and are-uncovered when the pistoinmovesmpwardly in th'eeylinder:

- Before :describingrthetoperationzoff th'e'piston, it is best. firstrtorset:forthzthatnthe;uppersend 1 .ofifthe cylinder rsceivesizthe innenendiofsaaguide sleeve-:6, ,see :Eig'nrert;

Patented Apr. 3, 1956 the exhaust ports for This guide sleeve has an outwardly-extending annular flange 11 that rests against the top of the cylinder A, as clearly shown in Figure 5. A retaining flange nut 12 is threaded upon a threaded outer portion 13 of the upper end of the cylinder A and the nut acts as a fastening means for holding the guide sleeve C to the cylinder A. Within the guide sleeve C, I reciprocably mount a plunger D, see Figure 3, and this plunger carries a pin 14 that extends transversely therethrough and has its ends slidably received in guide slots 15 that are provided in the guide sleeve C and are disposed diametrically opposite one another. The pin 14 performs the dual function of preventing rotation of the plunger D, while permitting a limited longitudinal movement thereof. The piston B on its outward movement will strike the plunger D and move it until the ends of the pin 14 reach the ends of the guide slots 15, whereupon further movement in the same direction is prevented.

A cutting implement such as a chisel E has its shank 16 provided with a notch 17 and the shank is also provided with a flattened portion 18 in line with the notch and disposed at the end of the shank. A leaf spring F is pivoted to the plunger D by means of a screw 19 and the inner end of this screw is positioned adjacent to the flat-' tened portion 18 on the shank 16 of the chisel E to prevent rotation of the chisel with respect to the plunger. The free end of the leaf spring F carries a detent 20 and this detent is slidably received in an opening 21 provided in the plunger D and is removably received in the notch 17 of the chisel shank 16 for holding it in place. The plunger D has a socket 22 for removably receiving the chisel shank 16. V

The work on which the chisel operates is indicated generally at G in Figure 3, and this may be a bone if the chisel is used for surgery purposes, or it may be a piece of wood or other material. When the pointed end 23 of the chisel is directed against the work G so as to shave 0d a portion as indicated at 24 in Figure 3, the forcing of the tool against the work will tend to move the plunger D inwardly in the guide sleeve C until the outward annular flange 25 on the plunger D strikes the outer end of the guide sleeve. This movement will cause ure 3. The plunger may be moved to close the inlet V the inner end of the plunger to move inwardly from the inner end of the guide sleeve so that the plunger will be in a position to be struck by the advancing piston B on its power stroke. The piston in its reciprocations will therefore drive the plunger D and the chisel E outwardly, while the force of the chisel on the work will drive the plunger inwardly as soon as the piston B has delivered its blow and starts on its return movement within the cylinder. The pin 14 holds the plunger D from flying clear of the cylinder A when the piston B strikes it.

I will now describe the means for conveying a compressed gas to the cylinder A and for conveying the spent or exhaust gas to the rear of the instrument so that this gas will not contaminate the operative area when the device is used for surgical purposes. Referring to Figure 1, it will be seen that I make use of a portable tank indicated generally at H and this tank may contain any kind of compressed gas or air desired. It is best to use carbon dioxide if the instrument is to be used for surgical purposes because this gas cannot be ignited by a spark.

The tank H is provided with a main valve 26 and this controls the flow of the compressed gas to a pressure regulator indicated generally at I. A control handle 27 is mounted on the pressure regulator I and delivers the compressed gas at the proper pressure to a flexible hose 28. The control handle 27 may be adjusted so that the gas will be delivered to the instrument at a desired pres sure and a pressure gauge K will indicate this pressure. A shutoff valve L is placed in the flexible line 28 and this valve is opened when the instrument is to be used. If desired, a foot-control valve indicated generally at M is placed in the flexible line 28 and this will shut off the flow of gas to the instrument until a foot pedal 29 is depressed for opening the foot-control valve.

Now referring to Figure 3, it will be seen that the flexible hose 28 that carries the compressed gas has its free end attached to a conical surface 30 of an inlet tube N. A nut 31 clamps the outer end of the hose to the control end 3! and makes a gas-tight seal therewith. Figure 8-shows the inlet tube provided with a hand control cutoir" valve P. Figure 3 shows the valve P provided with a plunger 32 and this plunger has a passage 32 that is aligned with the bore 33 provided in the inlet tube N when the plunger is in the position shown in Figpassage 33.

The inlet tube has its upper end permanently secured to a cup-shaped part Q, see Figure 8. The outer surface of this cup-shaped part Q is provided with a plurality of longitudinally extending and spaced-apart grooves 34. Figure 8 shows the exhaust ports 10 registering with certain of these grooves-34. Figure 4 illustrates how the upper end of the cup-shaped member Q is internally threaded at 35, andthese threads receive the threads 36 on the outer surface of the cylinder A, see Figure 5. The exhaust ports 10 in the cup Q register with the exhaust ports 10 in the cylinder A.

The lower end of the cylinder A is closed by means of a disc R and this disc is shown in Figures 5 and 7. The disc has pins 37 that are received in recesses 38 provided in the lower end of the cylinder A. When the disc R is in place to close the lower end of the cylinder, it will be seen from Figures 5 and 7 that the inlet ports 39 in the disc will register with inlet passages 40 that extend longitudinally in the cylinder A from a lower end thereof up to the annular grooves 2 so as to communicate therewith. An annular shoulder 41 is provided within the interior and at the bottom of the cup-shaped portion Q, seeFigure 4, and this shoulder spaces the disc R above the bottom of the cup so that the compressed gas can flow from the passage 33 of the inlet tube N, into the passages 40, see Figure 3, and then into the annular groove 2.

When the piston B is in its intake position as shown in Figure 3, the compressed gas will flow from the annular groove 2 and enter both ends of the transverse passage 8 in the piston B. The compressed gas will then flow downwardly through the passage 6 from the passage 8,

and will enter the lower compartment A1 of the cylinder.

It will be seen that the compressed gas will force the piston B upwardly on a power stroke to strike the inner end of the plunger D and cause the chisel to cut the work G as indicated at 24 in Figure 3.

When the piston B nears the top of its power stroke, as shown in Figure 4, it will uncover the exhaust ports 10 and permit the trapped compressed gas to pass through these ports and enter the grooves 34 and flow downwardly in these grooves. An outer sheath S covers the tops of the grooves 34 so as to form them into passages. Figure 4 shows the sheath as telescoping over the cylinder A as well as over the cup-shaped member Q and as having a flange 42 at its top that is received in an annular groove 43 formedat the top of the cylinder A. The hexagonal nut 12 holds the flange 42 in the groove 43.

An outlet tubular member T, see Figures 3 and 4, has one end secured to the outer sheath S by the screw threads 44 and this tubular member is spaced from the inlet tube N so as to provide an annular exhaust passageway 45 that will lead the exhaust gases to the rear end of the instrument as shown in Figure 4, which is at a remote point from the chisel E. A

From the foregoing description of the various parts of the device, the operation thereof may be readily under.-

stood.

The tool maybe held in the hand in much the same manner as a fountain pen." The thumb and forefinger can grip the smooth cylindrical portion 46, see Figure l, of the outer sheath S, and the knurled outer surface '41- of the outlet tubular member T will rest on the portion of the same hand that connects the thumb with the index finger. The operator can support his hand when using the tool by resting the tops of the fingers that do not contact with the instrument, on the work being acted upon and he can guide the pointed end 23 of the chisel E against the work with a high degree of skill. Delicate control is possible when using the tool in this manner.

Both the shutolf valve L and the hand control valve P are moved into open position. The foot pedal 29 may be used for controlling the foot valve M. It is not necessary that both valves M and P be used. The compressed gas will flow through the inlet passage 33 of the inlet tube N when the valve M is opened and then will flow through the openings 39 in the disc R to enter the longitudinal passages 40 in the cylinder A. The gas will then flow into the annular groove 2 and thence into the transverse passage 8, the longitudinal passage 6, in the piston B, and will enter the lower chamber A1 of the cylinder. The piston will be moved on its power stroke by the gas trapped in the lower chamber A1 and forcing against the bottom of the piston to move it upwardly. Any trapped gas in the cylinder bore 1 which is above the piston will escape through the bleed outlet 9 and will enter the space between the sheath S and the outer surface of the cylinder A. From here the trapped gas can flow along the grooves 34 and out through the exhaust passage 45.

The upward movement of the piston B from Figure 3 to Figure 4, on its power stroke, will cause the piston to strike the plunger D and move it together with the chisel against the work G. When the piston is in its uppermost position, the inlet bore 8 in the piston, will be out of registration with the inlet groove 2 and therefore no more compressed gas can enter the

bores

8 and 6. The upward movement of the piston will uncover the exhaust ports 10 and permit the compressed gas in the cylindrical compartment A1 to escape therethrough and to flow along the grooves 34, and out through the passage 45.

The piston is returned to its starting position by the compressed gas in the groove 2 bearing against the shoulder 5 on the piston, and by the fact that the piston upon striking the plunger D will rebound and start on its return movement. The compartment A1 has been relieved of its gas pressure and therefore the piston will move from the position shown in Figure 4 into that shown in Figures 3 and 5. The end of the return movement of the piston will be cushioned because the gas in the compartrnent A1 will be trapped as soon as the piston closes the exhaust ports 10. There will be no metallic sound from the piston as it returns in its movement and is ready to start on its next power stroke.

There will be no cushioning effect of the piston on its power stroke when striking the plunger D because any trapped gas in the upper part of the cylinder will escape through the bleed hole 9. As soon as the piston returns in its movement from the position shown in Figure 4 into that shown in Figure 3, the plunger D will also return in its movement because the chisel E is continually held against the work during the cutting operation. The pin 14 limits the outward movement of the chisel E as well as holds the chisel from rotating in the guide sleeve C.

The operator can control the instrument for delicate bone surgery and can stop and start the flow of compressed gas to the instrument by using either the foot valve M or the hand valve P.

Dry carbon dioxide is a relatively inert and a very stable compound. The gas inhibits the growth of or actually destroys bacteria. This germicidal action increases in line with the number of volumes of carbonation used. Therefore, using carbon dioxide under pressure to operate the device for surgical purposes will give an additional safety factor for the success of the operation. The inert gas will prevent any possibility of an explosion and it has fire extinguishing properties.

I claim:

1. A pneumatically operated tool comprising: a cylinder; a piston reciprocably mounted therein; a plunger placed at one end of the cylinder and adapted to be contacted by the piston; a guide for the plunger and secured to the cylinder; a cutting implement carried by the plunger; means for delivering gas under pressure to the cylinder for reciprocating the piston; said cylinder having exhaust ports uncovered by the piston when the latter moves in one direction; and a sheath enclosing the cylinder and having passageways communicating with the exhaust ports and extending beyond the end of the cylinder opposite to the plunger for delivering the exhaust gases at a point remote from the cutting implement.

2. A pneumatically operated tool comprising: a cylinder; a piston reciprocably mounted therein; a plunger placed at one end of the cylinder and adapted to be contacted by the piston; a guide for the plunger and secured to the cylinder; a cutting implement carried by the plunger; an inlet tube axially aligned with and operatively connected to the cylinder and adapted to deliver com pressed gas to the cylinder for reciprocating the piston; said cylinder having exhaust ports uncovered by the piston when the latter moves in one direction; and a sheath enclosing the cylinder and a portion of the inlet tube and forming an exhaust passage that communicates with the exhaust ports and extends to the end of the sheath enclosing the inlet tube.

3. A pneumatically operated tool as defined in claim 2, in combination with: a flexible hose connected to the inlet tube; a portable tank containing dry, germicidal, non-explosive carbon dioxide gas under pressure; said hose communicating with the tank; and a valve arranged for controlling flow of gas from the tank to the inlet tube.

4. in a pneumatically operated tool: a cylinder; a piston reciprocably mounted in the cylinder; at plunger mounted in one end of the cylinder and adapted to be struck by the piston when the latter moves in one direction; means for limiting the outward movement of the plunger; a cutting instrument removably carried by the plunger; an inlet tube extending from the opposite end of the cylinder to that of the plunger and being axially aligned with the cylinder; means for delivering gas from the tube to the interior of the cylinder for reciprocating the piston; said cylinder having a bleed opening disposed adjacent to the plunger and having exhaust ports placed nearer the opposite end of the cylinder; and a sheath enclosing the cylinder and a portion of the inlet tube and constituting a passage for any gases escaping from the bleed opening or from the exhaust ports.

5. A pneumatically operated tool comprising a cylinder; a piston reciprocably mounted therein; an instrument-carrying plunger disposed at one end of the cylinder, the plunger being struck by the piston each time the latter is reciprocated; an inlet tube having a cupshaped member enclosing the end of the cylinder disposed opposite to the plunger; said cylinder having intake passages placing the inlet tube in communication with the interior of the cylinder; said cylinder and cupshaped member having exhaust ports extending therethrough; the outer cylindrical surface of the cup-shaped member having longitudinally extending grooves that register with the exhaust ports; and a sheath enclosing the cylinder, the cup-shaped member and the greater portion of the inlet tube; said sheath being spaced from the inlet tube and constituting a passage for the exhaust gases from the grooves to the end of the sheath that surrounds the inlet tube; this end of the sheath opening to the atmosphere for permitting the escape of the exhaust gases. at a point which is remote from the instrument carried by the plunger.

Germany June 10, 1926