"Impacting Rock Breaker"

Technical Field

This invention relates to impacting rock breakers and in particular to means for providing an impacting force to the fracturing means thereof.

Background Art

In U. S. Letters Patent 3,868,145 of Delwin E. Cobb et al, which patent is owned by the assignee hereof, a rotary eccentric shaft drive is provided for mechanically driving the impact rock fracturing mech¬ anism. An impact member in the form of a ring is ro- tatably mounted on the eccentric shaft so as to be driven in an orbital path and thereby intermittently engage the fracturing mechanism shank. A reaction ring- constrains the ring impact member to rotate with respect to the eccentric shaft.

Another form of impacting apparatus is illus¬ trated in U. S. Letters 3,770,322 of Delwin E. Cobb et al, which patent is also owned by the assignee hereof. As shown therein, the impacting energy is stored in a flywheel and cyclically delivered by the transmission means to the work tool. The transmission means in¬ cludes an impact device and a substantially rigid ele- ment establishing a positive connection of the eccen¬ tric shaft mounting the flywheel to the impact device.

In U. S. Letters Patent 3,922,017 of Delwin E. Cobb, which patent is also owned by the assignee hereof, an impacting fracturing apparatus is operated by a drive shaft rotatably mounted in a housing and having an eccentric journal mounted thereon for ro¬ tation therewith. A rigid link is journaled at one

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end to the eccentric journal and pivotally connected to the impact member of the apparatus which is sup¬ ported by the housing member for impact engagement with an elongated fracturing shank pivotally mounted at one end to the housing member.

Disclosure of Invention

The present invention comprehends an improved impactor for use as a rock breaker or the like wherein the hammer is rotatably mounted to a crank for concur- rent revolution about the axis of the crank and rota¬ tion about a hammer axis extending parallel to the crank axis and revolved about the crank axis. The hammer defines a rounded contacting portion engaging the fracturing member. Means are provided for rotat- ing the hammer in synchronization with the crank ro¬ tation to move the contacting portion reciprocatively toward and from the force transfer member so as to cause the contacting portionof the hammer to impact against the force transfer member with a rotational engagement free of rolling movement therebetween.

In the illustrated embodiment, the crank is rotatably mounted in a housing and the means for ro¬ tating the hammer in synchronization with the crank rotation includes meshing gears on the housing and the hammer.

The contacting portion of the hammer, in the illustrated embodiment, defines a right circularly cylindrical surface portion engaging a complementary portion of the force transfer means. in the illustrated embodiment, the hammer surface portion defines a center point which is re¬ ciprocated rectilinearly as a result of the concur¬ rent rotation and revolution of the hammer about the crank and hammer axes.

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In the illustrated embodiment, the crank de¬ fines a recess for receiving the contacting portion of the hammer at the portion of its rotation most remote from the force transfer ^" means. Thus, the impactor structure of the present invention is extremely simple and economical of con¬ struction while yet providing an improved impacting functioning and affording a long, troublefree life of the apparatus. The impactor structure effectively minimizes the contact stresses on the impacting sur¬ faces of the apparatus and avoids large power losses as have occurred in the impactor structure of the prior art. Further, the novel rotational impacting action effectively lowers the noise level of the ap- paratus and effectively minimizes undesirable shaking forces.

Brief Description of the Drawing

FIGURE 1 is a fragmentary side elevation with portions broken away illustrating the construction of the impactor of the invention;

FIGURE 2 is a fragmentary horizontal section taken substantially along the line 2-2 of Figure 1;

FIGURE 3 is a fragmentary horizontal section generally similar to that of Figure 2 but illustrating the arrangement of the impactor structure shortly sub¬ sequent to the transfer of impacting force to the force transfer means;

FIGURE 4 is a fragmentary horizontal section showing the arrangement of the impactor at a slightly later time in the operation thereof;

FIGURE 5 is a fragmentary horizontal section illustrating the arrangement of the impactor upon still further rotation thereof; and

FIGURE 6 is a fragmentary horizontal section

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illustrating the arrangement of the impactor at the time the hammer is at its position most remote from the force transfer means.

Best Mode for Carrying Out the Invention i the exemplary embodiment of the invention as disclosed in the drawing, an impactor generally designated 10 is shown to include a fracturing means generally designated 11, a crank generally designated 12, a force transfer means generally designated 13, and a hammer generally designated 14.

As shown in Figure 1, the crank is rotatably mounted on a crankshaf 15 for rotation about a crank axis 16 by suitable rotatable drive means (not shown) . The crank is journaled in a pair of bearings 17 and 18 carried by a housing 19.

Hammer 1.4 defines a lobe 20 forming the con¬ tacting portion thereof adapted to impact against a link 21 of the force transfer means 13. As seen in Figure 2, the contacting portion 20 defines a right circularly cylindrical surface 22 which engages a complementary recess portion 23 of the link in the impacting engagement of the hammer with the force transfer means.

As shown in Figure 1, hammer 14 is journaled for rotation about a hammer axis 24 by a pair of bear¬ ings 25 and 26 at opposite sides of the contacting lobe 20. The bearings are retained on crank 12 by means of suitable bearing caps 27.

Thus, hammer 14 is mounted to crank 12 for revolution therewith about the crank axis 16. Con¬ currently with such revolution, the hammer is caused to rotate about hammer axis 24 by suitable gear means 28, including gear teeth 29 provided at one end of the hammer, and meshing gear teeth 30 provided on hous- ing 19.

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In the illustrated embodiment, the gear ratio is two-to-one so that a point P defining the center of the cylindrical contacting surface 22 reciprocates rectilinearly toward and from the link 21 as a result of rotation of the crank 12 about its axis 16. The resulting movement of the hammer 14 is illustrated in the sequential showings of Figures 2-6. As a result of this concurrent revolution and rotation of the ham¬ mer, the contact of surface 22 with link 21 in recess 23,providing the impact force to the link for effect¬ ing the rock breaking operation of the fracturing arm 11, is a rotational engagement free of rolling move¬ ment between the two members so that an extremely close fit is obtained therebetween for improved force transfer.

Referring more specifically to Figures 3-6, as the crank rotates in a clockwise direction from the position of Figure 2, axis 24 of the crank is caused to define a circle around the crank axis 16 while the point P is caused to move rectilinearly radially to and through the axis 16. Thus, as seen in Figure 3, point P is displaced radially toward axis 16 from its position in Figure 2 as the axis 24 of the hammer moves upwardly and to the right from its original po- sition.

As seen in Figure 4, when the axis 24 of the hammer is vertically above crank axis 16, point P co¬ incides with axis 16 and the contacting surface 22 of the hammer is lowermost. Referring to Figure 5, as continued clockwise rotation of the crank occurs, hammer axis 24 moves downwardly and toward the right while point P moves further radially away from axis 16.

Re erring to Figure 6, when the rotation of crank 12 is 180° from the position thereof in Figure 2, the hammer extends directly reversely to its extent

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in the position of Figure 2, with the contacting sur¬ face 22 extending directly radially away from the crank axis 16 and with the point P at its maximum right- hand position. At this time, the hammer axis 24 lies on the line of movement of the point P and, thus, di¬ rectly radially oppositely to its position at the time of impact, as shown in Figure 2.

As further shown in Figure 6, housing 19 is provided with a projecting portion 31 which receives the projecting portion 22 of the hammer in this dis¬ position.

As will be obvious to those skilled in the art, continued clockwise rotation of crank 12 causes a reversely similar revolution and rotation of the hammer so as to return the hammer to the impacting position of Figure 2, at which position the contact¬ ing surface 22 impacts against the link 21 to pro¬ vide a further momentary impacting force to be trans¬ ferred through the link to the fracturing arm 11. This transfer of impacting forces is repeated each time the crank is rotated 360° whereby the impacting rate is a function solely of the rate of rotation of the crank 12.

As illustrated in Figure 1, link 21 may be provided with a flange portion 32 which limits the reciprocal movement thereof in the link bearing 33 in which the link is slidably carried. As further shown in Figure 1, a seal 34 may be provided in a suitable recess 35 in the outer end of a link support 36 mounted to the housing 19 for supporting link 21 there¬ on. As further shown, the retaining ring 37 may be provided for removably retaining seal 34 in recess 35.

Industrial Applicability

Impactor 10 provides an improved impacting

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force transfer by causing the hammer to engage the force transfer means with a rotational movement free of rolling action therebetween, ^" whereby an improved oil cushion may be formed between the contacting sur- face 22 and link 21 in recess 23 thereof lowering the contact stresses on the impact surfaces and substan¬ tially reducing the noise level in the operation of the impactor.

Impactor 10 further provides a simple low cost construction which may utilize conventional bear¬ ings, such as crank bearings 17 and 18, and hammer bearings 25 and 26. The bearings may be of relatively small size for further simplified and economical con¬ struction. As discussed above, the bearings are dis- posed at opposite sides of the contacting portion 20 of the hammer so as to be displaced from the line of impact for reduced bearing losses and extended useful life thereof.

As the link 21 has a relatively small move- ent, the seal 34 provides a long troublefree life while yet permitting the force transfer means to ef¬ fectively transfer the high impact forces necessary to operate the-fracturing means 11.

As a result of the improved impactor struc- ture, a compact design may be realized further effec¬ tively minimizing the cost of construction.

As further illustrated, the housing, or case, 19 is of simple economical construction while yet pro¬ viding suitable bearing and gear mounting portions of the impactor.

As indicated above, the impactor is advanta¬ geously adapted for use as a rock breaker such as for use in mining, demolition, excavation, etc. , opera¬ tions. Other aspects, objects and advantages of this

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invention can be obtained from a study of the drawings, the disclosure and the appended claims. The foregoing disclosure of specific embodiments is illustrative of the broad inventive concepts comprehended by the in- vention.

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