US2071852A - Tool retainer - Google Patents

Description

G- M. NELL. ET AL TOOLf RETAINER 'Filed May 16, 1954 2 Sheets-Sheet 2 lNvE 50S/cve /14 4wd G- S/O/c/yen ATTORNEY Patented Feb. 23, 1937 UNITED' STATES TOOL RETAINER Gustave M. Nell and AlfredvG. Slatcher, Detroit, Mich., assignors to Chicago Pneumatic Tool Company, New York, N. Y., a corporation of New Jersey Application May 16, 1934, Serial No.725,840

1 Claim.

This invention relates to tool retainers more particularly designed for use in connection with percussive tools, such as rock drills, and functioning to prevent disengagement of the tool or drill steel from the holder when the tool is being withdrawn from the work.

An object of this invention is the provision of a tool retainer which may be conveniently attached to or detached from the tool holding device or machine. To attain this end, the retainer is so constructed and arranged that it can be attached or removed by simply hooking it on or unhooking it from the machine without requiring the removal of any other securing parts or the use of any prying tools or implements for forcing the retainer out of shape.

Another object of this invention is to enable the tool retainer to be held positively and at will in either the tool engaging position or out of the way of the tool or drill steel when it is desired to operate the drill.

A further object of the invention is the prevention of accidental disengagement of the retainer from the machine when the latter is in operation which might result from the vibration of the machine. In accordance with this object, positive locking means is provided which permits the retainer to be removed only when the drill steel is disconnected from the machine.

A still further object is to provide a vtool retainer and associated parts which are dependable in operation, inexpensive to manufacture and convenient to handle.

Other objects and features of the invention will appear more clearly from the following description taken in connection with the accompanying drawings and appended claim.

In the drawings:

Fig. 1 is a side elevation of a portion of a rock drill to which the present invention is applied, showing the retainer about to be connected to the machine;

Fig. 2 is a similar view showing the retainer and drill steel in engagement with each other;

Fig. 3 is a similar view showing the machine in condition for operation with the retainer disconnected from the drill steel;

Fig. 4 is a longitudinal section, as indicated by the arrows 4--4 in Fig. 2, but showing the lower portion of the retainer in elevation;

Fig. 5 is a bottom View of the front head of the drilling machine and the retainer collar; and

Fig. 6 is a cross-section, as indicated by the arrows 6--6 in Fig. 4, showing the trunnion ring mounted on the front head.

` The invention is illustrated in connection with a rock drill but it will be understood that the retainer may be employed to retain percussive tools of other types and even has a more general application for securing a tool of any suitable type against removal from its holder. Referring to the drawings, the rock drill may be of a conventional type provided with a front head IU in which is mounted a rotary socket II, which is shaped to fit and receive the polygonal portion of a drill steel I2. A piston I3 impinges against the upper end of the steel. The thrust of the drilling machine when pressed toward the Work is transmitted from the socket II to the drill steel through a collar I5 formed upon the latter. This collar also cooperates with the tool retainer I l to prevent disengagement of the steel when the drill is Withdrawn from the Work. The retainer I1 is adapted to be mounted upon trunnions I8 projecting from opposite sides of a trunnionring I9 which is sleeved upon the projection 20 at the lower end of the front head I0. As seen inFig. 6, the opening in the trunnion ring is generally round but provided with flats 2|, and the upper portion of the projection 20 is correspondingly shaped to receivethe ring loosely but hold it against rotation thereon. A spring 23, surrounding the projection 20 urges the trunnion ring upwardly and the lower end of this spring rests upon a retaining collar 24. As shown best in Fig. 5, the collar rests upon a pair of supporting lugs at the extreme lower end of the projection 2i). The opening in the collar 24 is recessed to provide a pair of slots 2'I extending for the full thickness of the collar by means of which the collar may be slipped over the lugs 25, and a pair of slots 28 extending for approximately one-half the thickness of the collar and adapted to receive the lugs after the collar has been slipped over the end of the projection Z and rotated for a quarter revolution. The diameter of the projection 20 in the immediate ,rear of and between the lugs 25 is slightly less than the distance across the flats 2| in the trunnion ring, thereby allowing the latter to be rotated so that the iiats on the front head and Jthe flats on the ring are in register. After the trunnion ring, spring and retaining collar have been assembled on the front head, the trunnion ring I9 is yieldingly held in engagement with the shoulders 3B, Fig. i on the front head, and is in condition to receive the retainer I'I.

The retainer I 'I is preferably made of one piece and comprises two parallel arms 3l spaced apart to clear the spring 23 when the retainer is swung about the axis of the trunnions I 8. The lower ends of the arms converge toward each other and terminate in a U-shaped portion or yoke 32 adapted to partially encircle the drill steel I2 as shown in Fig. 2. This yoke is adapted to engage the collar I5 on the drill steel in case the latter becomes stuck in the hole when the drilling machine is withdrawn from the Work. To prevent the retainer from accidentally swinging out of engagement with the drill steel when an outward pull is exerted thereon, locking shoulders 34 are formed on the yoke 32 which are positioned to be on the opposite side of the steel .with respect to the central portion 35 of the yoke and engageable with the collar I5. Thus, when the drill is drawn outward, the collar I5 will slide from its normal position against the socket lI into position where it bears against the yoke 32 and in this position the shoulders 34 will prevent swinging of the yoke into disengaged position. On the other hand, when the `collar I5 is in normal position, it will not interfere with the outward swing of the retainer so that the steel may be detached or replaced at any time.

An important feature of the present invention resides in the swivel connection between the upper ends of the arms 3l and the trunnions I8. Each arm is apertured to provide a bearing 31 for its associated trunnion, and an open slot 38 extends between this bearing and an edge of the arm, by means of which the trunnion may be inserted into its bearing. On one side of the slot, the arm has a cam surface disposedat an acute angle with respect to a side edge 39 of the arm which is adapted to slide over the shoulder 30e during the assembly of the retainer. 'When the retainer is moved in the direction of the arrow in Fig. l, the cam surface 40 forces the trunnion ring downwardly against spring pressure until the trunnions are received within the bearing surfaces 31 of thel retainer. The latter may then be swung counter-clockwise to the Fig. 3 position where it is out of the way of the drill steel and to the Fig. 2 position when it is desired to withdraw the steel from the work. In each of these two positions of adjustment, the retainer is held against accidental displacement by bearing against the shoulders 3IJa on the iront head, and for this purpose the upper ends of the arms 3l have flat edges 4I and 42 for engaging said shoulders in the respective positions of adjustment. The resilient pressure of the spring 23 yieldingly locks the arms in engagement with the shoulders but permits swinging of the retainer by the application of force.

The drill is usually operated with the retainer connected thereto but in inoperative position as shown in Fig. 3. Due to the open slot 38, there is a tendency for the retainer to creep to the left under the vibrations of the machine and, without the provision of a safety device this movement might cause the retainer to unhook itself from the trunnions. To obviate this result, the present invention provides a lug 44 on one or both of the arms 3I adapted to engage the stop shoulders 3llb and thus prevent substantial movement in the disengaging direction.

In order to remove the retainer from the. drill, the steel is rst removed from the socket thereby permitting the retainer to be swung to the Fig. 1 position. Movement of the retainer to the right unhooks the same from the machine without requiring any implement for forcing the arms apart or deforming the retainer in any way.

What we claim is:

A rock drill comprising a front head, a socket mounted therein for receiving a drill steel, a laterally projecting shoulder on' one side of the front head, said shoulder having a flat lower edge, a trunnion ring sleeved over the front Vhead and having a trunnion projecting therefrom and disposed below said shoulder, resilient means acting on said ring to urge .the trunnion toward said shoulder, a retainer for said drill steel adapted to swing about said trunnion as an axis, said retainer comprising an arm having an open slot to receive the trunnion and a flat edge for engaging said shoulder during the assembly of the retainer, one edge of the slot adjacent the open end portion thereof being disposed at an acute angle with respect to said flat edge to cooperate therewith to form a wedge adapted to move the trunnion against said resilient means.

GUSTAVE M. NELL. ALFRED G. SLATCHER.

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