US3214073A

US3214073A - Splinter-guards of explosively actuated power tools

Info

Publication number: US3214073A
Application number: US238382A
Authority: US
Inventors: Rosselet Claude
Original assignee: Sarmi S A Soc D Applic De Rech
Current assignee: Sarmi S A Soc D Applic De Rech; Sarmi Sa D'applications De Recherches Minieres Et Industrielles Ste
Priority date: 1961-11-23
Filing date: 1962-11-19
Publication date: 1965-10-26
Anticipated expiration: 1982-10-26
Also published as: BE624992A; FR1339365A; DE1503047B2; CH382083A; DE1503047A1; ES282695A1; NL285786A; GB1019264A; NL126340C

Description

Oct. 26, 1965 c, RQSSELET 3,214,073

SPLINTER-GUARDS OF EXPLOSIVELY ACTUATED POWER TOOLS Filed Nov. 19, 1962 3 Sheets-Sheet 1 In venfor CLAUDE ROSfiELET 0a. 26, 19.65 RQS LET 3,214,073

SPLINTER-GUARDS OF EXPLOSIVELY ACTUATED POWER TOOLS Filed Nov; 19, 1962 s Sheets-Sheet 2 In van for 3 c cmupe 180551157 5 m im Oct. 26, 1965 c. ROSSELET 3,214,073

7 SPLIN'IER-GUARDS OF EXPLOSIVELY ACTUATED POWER TOOLS Filed Nov. 19, 1962 s Shets-Sheet 3 INVENTOR cm 1105 ROSSELET pV MmA /W ATTORNEYS United States Patent 3,214,073 SPLINTER-GUARDS 0F EXPLOSIVELY ACTUATED POWER TOOLS Claude Rosselet, Founex, near Nyon, Switzerland, assignor to Sarmi S.A. Societe dApplications de Recherches Minieres et Industrielles, Lenzerheide, Grisons, Switzerland, a Swiss company Filed Nov. 19, 1962, Ser. No. 238,382 Claims priority, application Switzerland, Nov. 23, 1961, 13,659/61 7 Claims. (Cl. 227-11) The present invention relates to the splinter-guards which are intended to be employed on explosively actuated power tools known as sealing guns, that is to say devices which are used for driving fastening articles such as pins into hard and compact materials such as cement, concrete or wood under the action of an explosive charge.

More particularly, the invention relates to eccentrically movable splinter-guards which can be brought manually into an eccentric position and which are fitted, on the one hand, with elastic restoring means allowing the splinter-guard to be moved from the normal centered position into said eccentric position and, on the other hand, with locking means for temporarily maintaining the splinterguard in said eccentric position despite the force of the elastic restoring means when said means have been brought under tension as a result of the eccentric positioning operation.

The present invention has for its object to provide, when the splinter-guard has been brought to the eccentric position by the operator, for the automatic return of said splinter-guard into the normal position, when the tool is fired, said automatic return being the result of the firing action.

Preferably, maintaining the splinter-guard in the eccentric position would be possible only by the use of a detachable safety means.

Thus, according to the invention, an eccentrically movable splinter-guard with elastic restoring means which tend to bring back and maintain the eccentrically movable portion of the splinter-guard in the normal centered position with respect to the tired portion (which is mounted on the tool) of said splinter-guard, and comprising locking means which are able to be manually operated, is characterized in that said locking means are adapted to be responsive to the firing action, so that, on the one hand, the eccentrically movable portion of the splinterguard which is brought manually into the off-center position is locked in this position in opposition to the elastic restoring means and, on the other hand, said locking means are capable of returning themselves, under the firing action, into the unlocked position in which the said eccentrically movable portion returns to the centered position under the action of the restoring means.

Further particular features and characteristics of the invention will be brought out by the description which follows below of one example of construction of the new improved splinter-guard, said example being diagrammatically illustrated in the accompanying drawings, in which:

FIG. 1 :is a view at large scale and in cross-section parallel to the pivotal axis of the eccentrically movable portion of the splinter-guard showing the manually operated locking means in the position in which a manual control unit is locked by the safety means;

FIG. 2 is a view in cross-section taken along the line II-lI of FIG. 1;

FIG. 3 is a view similar to FIG. 1, the locking means having been released by the safety means;

FIG. 4 is a view in cross-section taken along the line IVIV of FIG. 3; e

3,214,073 Patented Oct. 26, 1965 FIG. 5 is a plan view (from the rear), at a reduced scale, of the complete splinter-guard unit in the normal centered position;

FIG. 6 is a plan view similar to FIG. 5, showing the splinter-guard in the eccentric position;

FIG. 7 is a view in cross-section taken along the line VIIVII of FIG. 5, showing the splinter-guard mounted on the front part of an explosively actuated power tool.

FIG. 8, lastly, is a developed view, in cross-section along the line VIIIVIII of FIG. 6, showing the return spring arrangement of the splinter-guard.

In the embodiment shown in the drawings, the reference 1 designates a fixed part of the splinter-guard, said fixed part being off-center with respect to a sleeve 2 and integral with said sleeve. The sleeve 2 comprises two sleeve members 2a and 2b and serves for the purpose of mounting the splinter-guard on the forward tool part A and is co-axial with the tool barrel B. The eccentrically movable part 3 of the splinter-guard is adapted to pivot on the part 1 about a finger 18 (located on the center x) of said part 1, said finger 18 engaging a hole 20 of the movable part 3. In an arcuate recess 19 of the part 1 is housed a return spring 16 which is in abutment against an end wall 19a of said recess 19 and against a stop member 17 integral with the part 3, and which tends to bring back said eccentrically movable part 3 into the normal position shown in FIG. 5. In order to allow an easy handling or bearing of the tool together with the splinter-guard, the sleeve member 2a is surrounded by a rubber grip P.

The fixed part 1 of the splinter-guard carries a box 4 inside which are formed two cylindrical chambers 5 and 9having their axes at right angles to each other and opening into each other to a small extent. The axis of the chamber 5 being parallel to that of the sleeve 2. Inside the cylindrical chamber 5 can slide a piston 6 which forms a locking member and the front part of which is capable of passing freely an opening 7 which is bored in the part 1 and is in register with the chamber 5. The eccentrically movable part 3 of the splinter-guard is provided with a frusto-conical hole 8 which, when the part 3 is located in the elf-center position shown in FIG. 6 accordingly moves to come in register with the opening 7. The front end of the piston 6 terminates in a frustoconical portion 6a having a shape which corresponds to that of the hole 8. The piston 6 additionally comprises a circular groove 6b and the rear end thereof terminates in a tail-piece 60 which projects from the box 4.

There is located, inside the chamber 9, a barrel or drum 10 which is adapted to rotate and to slide axially inside said chamber and which is normally thrust forwards by a restoring spring 11 bearing on the base 12 of a stem 13 which is intended to receive the bored rod of a safety key C. There is additionally provided inside the chamber 9 an oblique seating, or rib, 9a which is intended to maintain the drum 10 in a well-defined angular position, said diagonal seating being designed to cooperate, when the drum is in the forward position, with a corresponding oblique groove 10c cut in said drum.

The drum 10 is provided, in addition to the axial bore into which the key is intended to be fitted, with a recess 10a for the key web. In the normal condition (that is to say when the key is withdrawn), the drum 10 projects inside the chamber 5 and accordingly penetrates inside the groove 6b of the piston 6, thereby locking said piston axially in the position shown in FIGS. 1 and 2. In this position, a locking between the

parts

1 and 3, when the latter has been brought in the eccentered position, is made impossible.

A flat portion 10b is also milled in the drum 10 and permits the sliding movement of the piston 6 when said drum has been brought, by means of the key, into the position shown in FIGS. 3 and 4.

Finally, there has been formed in the front wall 15 which closes the chamber 9 a keyhole which is suitably orientated in order to ensure that when the key is withdrawn, the drum is necessarily located in the position shown in FIGS. 1 and 2 (piston 6 locked in inoperative position).

The splinter-guard which has just been described operates as follows:

When there is no key present, the drum is accordingly immobilized in the axial and angular positions represented in FIGS. 1 and 2, wherein the hollowed-out portion of said drum is engaged with the diagonal seating 9a under the action of the spring 11, whereas the piston 6 is locked in its top position. The operator is always able, as a result of a manual operation, to bring the part 3 of the splinter-guard into the off-center position shown in FIG. 6, but, as soon as it is released, said part returns, under the action of the spring 16, into the normal position shown in FIG. 5.

In order to lock the part 3 of the splinter-guard in the otf-center position, it is necessary to push axially the drum 10 by means of the key C (and in opposition to the thrust applied by the spring 11) and to cause said drum to rotate, again by means of said key, through an angle of approximately 90, so as to bring said drum into the position represented in FIGS. 3 and 4. At this moment, after having brought the part 3 of the splinterguard into the off-center position, the operator can press on the tailpiece 6c of the piston 6 so as to thrust this latter downwards and engage its frusto-conical part 6a inside the striking-plate hole 8 of the eccentrically movable part 3 of the splinter-guard said part 6a being jammed in the hole 8 under the action of the torque developed by the return spring 16 on the movable part 3 with respect to the fixed part 1. At this moment, the elements of the splinter-guard take up the position which is represented in FIG. 6. This FIG. 6 and FIG. 8 show the spring 16 in its compressed state.

However, at the time of firing, due to the recoil phenomenon, together with the shaking, or rattling, of the different parts of the splinter-guard, the forward end 6a of the piston 6 is no longer jammed in the hole 8, so that the spring 11 moves back said piston. The result is that the eccentrically movable part 3 of the splinterguard returns immediately into the centered position shown in full lines in FIG. 5. It is to be noted that the automatic release of the piston 6 is improved by the frusto-conical shape of the forward end 6a of said piston and the corresponding shape of the hole 8, although said frusto-conical shape is not essential.

Each time the part 3 of the splinter-guard is locked in the elf-center position, the piston 6 must be driven downwards, which is possible only insofar as the safety key remains engaged inside the drum and is in the unlocking position (as shown in FIG. 3).

As soon as the key is withdrawn, the drum 10 is automatically brought back and maintained in the locking position shown in FIGS. 1 and 2, thereby making it impossible to maintain automatically the part 3 of the splinter-guard in the off-center position.

It is thus ensured that the operator cannot use the splinter-guard, either as a result of inadvertence, negligence or laziness, in the ofi-center position thereof. The key can be in the care of a responsible person in charge who relinquishes possession of it in order to entrust it to the operator only with a view to permitting the execution of special operations. Such special operations can neverthless be carried out even in the event of loss of the key, but it is then necessary for the operator to exert an effort in order to maintain the splinter-guard in the off-center position while firing and to overcome the force of the return spring 16, which is always loaded, as a result of the eccentric positioning operation.

It is obvious that the example of embodiment of the new improved splinter-guard which has been described in the foregoing and as illustrated in the accompanying drawings has been given solely by way of indication and not in any limitative sense and that any detail modification can be made therein.

What I claim is:

1. In a splinter-guard for explosively actuated power tool, of the type comprising a fixed part intended to be mounted on said tool, a movable part which is rotatably coupled to said fixed part in such manner as to be capable of displacement off-center with respect to said fixed part about an eccentric motion axis, a return spring coupled to said fixed part and to said movable part so as to bring back and maintain the eccentrically movable part in a centered position with respect to said fixed part, the provision of: a box integral with said fixed part and provided, on the one hand, with a first cylindrical chamber parallel to the eccentric motion axis and, on the other hand, with a second cylindrical chamber having an axis at right angles to the first cylindrical chamber and intersecting said first chamber and further provided, at one end thereof, with a stop-catch; a piston adapted to slide in said first chamber and having a circular groove formed substantially at the level of the second chamber, and that end of said piston which is directed towards the movable part of the splinter-guard in which is formed a frusto-conical hole being designed to terminate in a frusto-conical portion intended to penetrate into said hole for the purpose of angularly locking the movable part with respect to the fixed part of the splinter-guard; a cylindrical drum, rotatable inside the second housing, capable of carrying out therein an axial movement, provided on that side turned towards the stop-catch with engagement means adapted to come into engagement with said stop-catch, designed to receive a control key, engaged under normal conditions with the groove of the piston so as to immobilize said piston, and provided laterally with a flat portion which, when said drum has been moved into a suitable position by means of said key, permits the free movement of said piston; and a restoring spring located inside the second chamber for thrusting back the drum axially and bringing the engagement means of said drum into engagement with the stop-catch, so as to secure said drum against rotation in a position in which the piston is thereby immobilized in the inoperative position.

2. In a splinter-guard for explosively actuated power tool, of the type comprising a fixed part intended to be mounted on said tool, a movable part rotatably coupled to said fixed part in such manner as to be capable of eccentric movement with respect to said fixed part about an eccentric-motion axis, return spring coupled to said fixed part and to said movable part so as to bring back and maintain the eccentrically movable part in a centered position with respect to said fixed part, and manually operable locking means, for locking, into the oif-center position, the eccentrically movable part of the splinterguard when the latter has been brought manually into said position, in opposition to the return spring, said locking means comprising: a box secured to said fixed part and having therein a cylindrical chamber open at both ends and the axis of which is parallel to the axis of motion of said movable part; a piston located in said chamber for sliding therein and having a rear end and a front part both protruding from said chamber; hole means provided in the movable part, so located as to register with the axis of said chamber, when the movable part has been brought in said eccentric position, and adapted for receiving the front part of said piston when a thrust is exerted on the protruding rear part of said piston.

3. A splinter-guard as claimed in claim 2 in which the front part of the piston has a frusto conical forward end whereas the hole means has a frusto conical shape correspinding to the shape of said forward end.

4. A splinter-guard as claimed in claim 2, further comprising a safety means coupled to said box and so adapted that said piston can be actuated by hand only when said safety means is, in turn, actuated by a removable control means.

5. A splinter-guard as claimed in claim 4, in which the safety means consists of a lock adapted to be capable of releasing the piston, while the removable control means consists of a key adapted to actuate said safety means.

6. A splinter-guard as claimed in claim 2, in which the piston is provided laterally with a hollowed-out portion and the box is provided, in addition to the chamber for the movable piston, with a second cylindrical chamber having its axis perpendicular to the axis of the piston chamber and which intersects the said piston chamber, said splinter-guard additionally comprising a cylindrical drum inside said second chamber and adapted to be rotated by a removable control and safety key, said drum, which is normally engaged in the hollowed-out portion of said piston for the purpose of locking said piston in its inoperative position, being provided laterally with a fiat portion which, when said drum is brought into a suitable angular position by means of said key, permits the free movement of said piston.

7. A splinter-guard as claimed in claim 6, in which the rotatable drum is provided, at one end thereof, with engagement means and is further adapted to slide axially inside the second chamber of which one end is fitted with engagement means which are complementary to those of the drum, while said second chamber further comprises a restoring spring which is disposed inside said second chamber for thrusting back the drum axially and to cause the engagement means of the drum to be brought into engagement with those of said second chamber, in opposition to the thrust which can be applied to said drum by means of the key, in order to disengage said drum.

References Cited by the Examiner UNITED STATES PATENTS 2,700,764 2/55 Catlin et a1. 144.5 2,869,127 1/59 Williams 144.5 X 2,952,020 9/60 Schulz l44.5 3,060,438 10/62 Elliott 144.5

FOREIGN PATENTS 615,276 2/61 Canada.

GRANVILLE Y. CUSTER, 111., Primary Examiner.