US2006065A

US2006065A - Portable power hammer

Info

Publication number: US2006065A
Application number: US708682A
Authority: US
Inventors: Joseph H Blake
Original assignee: Individual
Current assignee: Individual
Priority date: 1934-01-27
Filing date: 1934-01-27
Publication date: 1935-06-25
Anticipated expiration: 1952-06-25

Description

J1me 1935' J. H. BLAKE 2,006,065

PORTABLE POWER HAMMER Filed Jan. 27, 1934 INVENTOR 2 .5%); m Blake 5- z rfi Patented June 25, 1935 UNITED STATES PATENT oFFlcE 2,006,065 FORTABLE POWER HAMMER Joseph H. Blake, Seattle, Wash.

Application January 2'7, 1934, Serial No. 708,682

4 Claims.

My present invention relates to the art of power driven striking devices and more particularly to a portable power hammer.

My invention contemplates a portable striking unit which is so arranged that it may be made in a wide vanety of sizes suitable for-riveting, chipping and calking and is very nicely adapted for drilling as in rock and concrete. To facilitate this latter operation I have provided means for turning the drill bit so that a free cutting hole can be accomplished without any danger of the bit being driven in and locked in place.

The principal object of my present invention is to provide a striking mechanism adapted to be raised against acompression spring by rotary cam means. i

A further object of my invention is to! provide, in addition to the cam and spring actuated striker, a drill turning arrangement which will move the drill around its axis a fraction of a revolution for each blow struck.

A further object of my present invention is to arrange for a drill revolving mechanism which will revolve the drill between each stroke of the striking mechanism and will utilize the time during which there is no striker load on the drill itself. A further object of my present invention is to so arrange the parts of my tool that a variable stroke can be applied to the tool without any outside adjusting parts.

Other and more specific objects will be apparent from the following description taken in connection with the accompanying drawing, wherein Figure 1 is a longitudinal sectional View thru a power tool made after the teachings of my invention. Figure 2 is a cross sectional view along the line of Figure 1. Figures 3 and 4 are sectional views taken along the line 33 of Figure 1, the same being illustrative of the mechanism employed to impart the turning movement to the drill.

Referring to the drawing, throughout which like reference characters indicate like parts, 6 designates generally, the striker of my tool. This consists of several associated parts, namely, the lower striker plate 8, the upper striker plate l and a. plurality of connecting guide rods I2. Secured to the upper plate [0 is a cam follower M which in the illustration I have shown as being provided with a tapered roller l5 which is adapted to engage cam it. In the present illustration I have indicated cam l6 as a portion of a drum cam. This is very desirable when it is used with a direct drive as illustrated. If the motor however, were set at right angles with the body of the striking mechanism it would be necessary to employ a face cam of the more conventional type. As illustrated in Figure 2, the cam occupiesonly a portion of a circle, consequently as soon as the upper limit has been reached the fol-- lower drops oh? the same and allows spring :8, which has been compressed by the rise of the cam, to throw the striker 6 down to the end of the tool thus releasing the energy stored within the spring.

To resist the twisting action of cam l6, as it lifts the follower, I provide a plurality of guide rods 12. These serve to secure together and space, plates 8 and I0 andfurther as they are adapted to slide within the fixed guide plate 20, follower I4 is thus securely held against rotation and consequently the entire striker assembly is moved upwardly against the compression of spring I8. I have illustrated cam l6 as driven by an electric motor 22. When such a motor is I used it should be of the high speed type, preferably mounted on anti-friction bearings as illustrated. The motor shaft extension 24, to which cam I6 is fixedly secured, is journaled within guide plate as at 26. Each of the various plates employed in the striking mechanism and as guide plates should be provided with suitable relief openings as 28 to permit a free circulation of lubricant and to prevent any air cushioning which might dampen and absorb a large portion of the energy so that the tool would lose its effectiveness as a striker. Motor 22 may be provided with any suitable switching arrangement as is illustrated at 30. However, it should be clearly understood that an electric motor does not form a necessary part of my tool. Any source of motor power might be supplied, in fact for outdoor work, in the demolition of concrete and thelike, a high speed gasoline motor after the order of the outboard motors can be very effectively substituted for the electric motor shown.

In Figures 3 and 4 I have illustrated my bit turning device. This mechanism consists of a ratchet and pawl arrangement which are included between two

fixed plates

32 and 34 which are fixedly secured, as is guide plate 20, to the housing 36. Ratchet 38 is slidably engaged by the striker bit 40 by means of the long keyway 4| and the tit key 42 formed as part of the ratchet 38. The length of keyway 4| must slightly exceed the maximum movement of the striker 6 which in turn is controlled by the height of the lifting surface of cam l6. Pawl 43 is adapted to engage ratchet 38 and is pivoted to a fixed pivot 44. It is retained in this operating position by a suitable spring as 46. This pawl is merely to hold the tool bit against backward movement. The actual turning of the bit is accomplished by pawl 48, which is pivotably secure-d to the cam arm 58, and has its own positionin spring 5i. Cam arm 56 is pivotably secured to the spaced

plates

32 and 3 5 on the pivot 52. It is disposed for engagement with the sliding cam 55, which cam is in turn fixedly secured and travels with plate 8 of the striker assembly. The extreme positions of cam E i are illustrated in Figures 3 and 4. This movement is sufficient to move ratchet 38 one tooth. A presser spring 5563 is employed to maintain lever 55 at all times in contact with cam 5%.

A tool of this order must necessarily be designed and built particularly for the Work intended and this will necessitate many variations of the mechanism illustrated. Striker as should preferably be provided with replaceable tip units so that damage or injury to the tip will not necessitate the replacement of the entire striker bit til. This has been indicated by the coupling member Bil. It has further been found desirable to employ a buffermeans as the spring which encircles bit it and is disposed to rest upon the fixed plates 32. Suitable packing means should be provided as the packing rin to prevent loss of lubricant which must be supplied to the striking mechanism itself to prevent ex'essive wear and heating.

The foregoing description and the accompanying drawing are believed to clearly disclose a preferred embodiment of my invention but it will be understood that this disclosure is merely illustrative and that such changes in the invention may be made as are fairly within the scope and spirit of the following claims.

Having thus fully described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In a power hammer the combination with a housing, a rotary cam shaft journaled there-in, an arcuate cam of said shaft, and operating means for the shaft, of a reciprocable striking assembly mounted in the housing having a cam roller in the path of the cam, a spring for actuat ing the assembly, a striker mounted in the assembly, a ratchet device connected to the striker, a spring pressed cam arm for actuating the ratchet, and a cam arm reciprocablewith the striking assembly for actuating thepivoted cam arm.

2. In a power hammer the combination with a housing, a rotary cam shaft journaled therein, an arcuate cam on said shaft, and operating means for the shaft, of a reciprocating striking assembly comprising a pair of spaced plates one of which is slidable on said shaft and a tie bolt, a cam roller mounted on the slidable plate, an intermediate plate fixed in the housing having a guide hole for the bolt, and an actuating spring interposed between the fixed plate and the other assembly plate.

3. In a power hammer, the combination with housing, having a pair of spaced plates, a reciprocable striking assembly mounted in the housing and including a cross-plate, and a striking bit journaled in said cross-plate and reciprccable in said spaced plates, of a ratchet wheel located between said spaced plates and mounted on the bit, a pivoted ratchet arm and a pawl pivoted thereon, and a cam arm mounted on said crcss-plate for co-action with the ratchet arm.

l. In a power hammer the combination with a housing, having a pair of spaced plates, a reciprocable striking assembly mounted in the housing and including a cross-plate, and a striking bit iournaled in said cross-plate and reciprocable in said spaced plates, of a ratchet wheel located between the fixed plates and mounted on the bit to turn therewith and permit reciprocation of the bit, a spring pressed retaining pawl for the ratchet wheel, a spring-pressed, pivoted ratchetarm, a spring pressed actuating pawl for the ratchet wheel pivoted on said arm, and a cam arm rigid with said cross-plate engaging said ratchet arm.

JOSEPH H. BLAKE. 1