US1792894A

US1792894A - Manually-supported power tool

Info

Publication number: US1792894A
Application number: US266965A
Authority: US
Inventors: Anthony H Collins
Original assignee: Chicago Pneumatic Tool Co LLC
Current assignee: Chicago Pneumatic Tool Co LLC
Priority date: 1928-04-03
Filing date: 1928-04-03
Publication date: 1931-02-17
Anticipated expiration: 1948-02-17

Description

Feb. 17, 1931. A. H. COLLINS MANUALLY SUPPORTED POWER TOOL Original Filed April 3. 1928 6 a z 1 W o 3 2 M 7. 0 u 9 M A y a a fl$fgfl J 1 w e 5 FL x R? s N W z, 4 .2 P 0/0 20/, z 4 7 6 7 Z 3 a M E 5 0. 8 5 A b Patented Feb. 17, 1931 a U -Iran STATES PATENT orricr; j

an'rnomr-n. counts, or. BRONXVILLE, NEW roux; Assmnoa 'ro omeaeo PNEU- IA'I'IC r001. courm,-or nnwyoax, n. Y., A conroaariou or NEW annsny ANUALm -SUProBTEn rowan. root? Application filed April}; 1928, Serial No.- 286;985. Renewed August 4, 1930.

' This invention relates to portable power,

; operated percussive tools adapted to be manually supported and directed to the work. It has practical application to tools for hand 5 drilling and demolition work generally.

i One object of the invention is to relieve the operator so far as possible of the sh ck and reaction of the tool when in operat on. Another object is to protect the percussion motor 10 of such a tool from the destructive efiorts of vibration. Other objects will be apparent from the detailed description which ollows:

In order to illustrate the invention one concrete embodiment thereof is shown in the '1 accompanying drawings in which:

Fig 1 is a vertical sectional view through the handle support and retainer portion of the tool showing the percusslve motor also partially in vertical section, the parts being no in the inoperative or non-runnmg pos1t1on of themotorfand Q p Fig. 2 is a view similarto Fig. 1 showing the parts in the running posltlon of tl1e motor.

'In the embodiment of the invention chosen for-the purpose of illustration, the tool comprises a cylinder 3 having an elongate axlal chamber 3a in which is mounted for hunted movement a percussive motor A, preferably of the fluid pressure type.. Cylinder 3 is arranged to be manually supported by aligned handles 4 which in the present instance are shown as forming part of a T head 5 which is secured to cylinder 3 in any suitable manner as by bolts (not shown). Since motor is indicated as of the fluid pressure type, head 5 preferably provides a connection at 6 for metive fluid and a throttle valve at 7,'wh1ch 1s controlled by a lever 8 conveniently arranged adjacent handles 4, the pressue fluid released by the throttle valve being directed into the rearward or handle end of chamber 311.

' Motor A has a head 9 slidably fitting the interior of chamber 3 and also has a reduced 45 portion or barrel 10 whichextends beyond cylinder 3, suitable supporting and packing means being provided on the cylinder including packing ring 171, packing 12, and gland nut 13. Within the piston chamber of motor 7 A reciprocates a hammer piston 14' which is controlled by an automatically throviin sleeve valye 15 moving in timed relation with the piston within a valve box 16 providedwith a cap 17 held in place by a backhead 18, the latter having bores 18a therethrough to admit motive fluid from the rear emYof chamber- 3a to the motor.

Packings

18 and 20 are arranged at opposite endsofmotQr head-Q and intermediate these packings vtlie head is reduced by an annular groove providing a chamber 21 into which the percussive-motor A exhausts. r T v f The working tool or drill bit B extends into the barrel ,10 of motor A to receive the blows of hammer piston 14 and is preferably formed with a collar 6 which not only serves to limit the extent of the bit shank within the barrelbut also cooperates with a. retainer 22 secured to the front end of cylinder 3 and of suflicient length to permit the movement of 3 motor A within cylinder 3. Cylinder 3 has a series of radial exhaust ports 23 in a plane substantiallycentrally of chamber 30.

Encircling the reduced portion or barrel 10 of the motor A and disposed within the annular chamber provided between the latter and the 'cylinder 3 is) a coil spring 24 which bears against motor head 9 on the one hand and cylinder ring 11 on the other and normally maintains motor A inwardly of cylinder To prevent motor A from striking head 5' when driven inwardlyby the action of spring 24, suitable buffer means. such as a rubber annulusz25, may be providedin the rear end of ehamber 3a to be contacted by motor head '18 and thereby limit. the rearwanl movement of motor A.

In operation the opening ofthrotlle valve 7 admits motive fluid to the rear end of chamber 3a, the motive fluid innnediately becoming effective against the full area of motor head 18, with the result that motor A is driven forwardly in cylinder 3 against spring 24 (or cylinder 3 is driven rearwardly against such pressure as the operator may be applying to handles 4). -When relative movement of motor A and cylinder 3 has reached the point where exhaust ports 23 register with exhaust chamber 21, percussive motor A goes into operation and con- Ell tinues in operation so long as it can exhaust through ports 23. To this end it is necessary that the operator apply sufficient pressure to handles .4 to balance, with the assistance of spring 24, the air pressure upon backhead 18 of the motor. When the throttle valve is closed and the pressure in the rearward end of chamber 3w vents to atmosphere through motor A, spring 24 moves motor A rearwardly or cylinder 3 downwardly until the motor is in-inoperative position as disclosed in Fig. 1.

While a preferred form of the invention has been herein shoWn and described, it is to be understood that the invention is not limited to the specific details thereof, but

covers all changes, modifications, and adap-' tations within the scope of the appended claims.

T claim as my invention:

1. A hand supported percussive tool comprising in combination a member having a handle and providing an elongate chamber, a fluid pressure percussive motor movable within said chamber, fluid pressure inlet means in said member adjacent said handle, the admitted pressure fluid being effective first to move said motor forwardly in said chamber and thereafter to operate said motor, and means wholly independent of the pressure fluid for opposing forward movement of said motor and for movlng said motor rearwardly when the pressure fluid is no longer admitted.

2. A hand supported percussive tool comprising in combination a member having a handle and providing an elongate chamber, a fluid pressure percussive motor movable within said chamber, fluid pressure inlet means in said member adjacent said handle, the admitted pressure fluid belng eflt'ective first to move said motor forwardly in said chamber and thereafter to operate said motor, means wholly independent of the pressure fluid for opposing forward movement of said motor and for moving sa d motor rearwardly when the pressure fluid is no longer admitted, and a resilient buffer for checking the rearward movement of said motor.

3. A fluid pressure tool comprising a cylinder member having a T handle and means including a throttle valve on said member for controlling the admission of pressure fluid to the chamber of said cylinder member, a fluid pressure motor movable as aunit within said chamber in one direction by.

the pressure fluid admitted thereto, means permitting operation of said motor by said admitted pressure fluid only when said motor is at a certain position within said cham her, and means for resisting movement of said motor by said pressure fluid and tending to maintain said motor at said certain operative position.

4. A fluid pressure tool comprising 8. cylinder member having a T handle and means including a throttle valve on said member for controlling the admission of pressure fluid to the chamber of said cylinder member, a fluid pressure motor movable as a unit within said chamber in one direction by the pressure fluid admitted thereto, means permitting operation of said motor by said ad- Initted pressure fluid only at certain posit1ons of the latter in said chamber, said means including one or more exhaust ports through said member, and means including a sprin for resisting movement of said motor by said pressure fluid tending to maintain said motor at said certain operat1ve position.

5. A fluid pressure tool comprisin a cylinder member having a T handle an means including a throttle valve on said member for controlling the admission of pressure fluid to the chamber of said cylinder member, a fluid pressure motor movable as a unit within said chamber in one direction by the pressure fluid admitted thereto, means permitting operation of said motor by said admitted pressure fluid only when said motor is at a certain position within said chamber, and means wholly independent of said admitted pressure fluid for resisting movement of said motor by said pressure fluid and tending to maintain said motor at said certain operative position.

6. A fluid pressure tool comprising a cylinder member providing an elongate chamber and having a T handle, means including a throttle valve on said member for controlling the admission of pressure fluid to said chamber, a fluid pressure motor movable as a unit in said chamber by the pressure fluid admitted thereto, means permittin operation of said motor by said pressure uid only at certain positions in said chamber including radial ports through said member, and means wholl independent of the pressure fluid for resisting movement of said motor by the pressure fluid and for moving said motor to a non-operative position within said chamber, said last named means comprising a coil spring encircling a portion of said motor within said chamber and arranged to be com ressed by the movement of said motor by t e pressure fluid.

Signed by me at New York, in the county of New York, and State of N. Y. this 31st day of March, 1928.

A. H. COLLINS.