Block dressing apparatus and method

An apparatus and method for dressing marginal areas of externally viewable surfaces of a building block. The apparatus includes at least one chipper having rotational axis and a plurality of outwardly extending teeth randomly disposed thereabout. The chipper is positioned and oriented so that its teeth may effectively work a predetermined marginal area of interest. As the predetermined marginal area of interest and the teeth of the chipper are brought into contact with each other, portions of the marginal area are randomly impacted and fractured to form an erose or jagged surface that resembles hand dressing. The apparatus may also include additional chippers, each having a rotational axis and a plurality of teeth randomly disposed thereabout.

BACKGROUND OF THE INVENTION

This invention relates generally to structures that may be built using masonry blocks. More particularly, this invention relates to an apparatus for and method of dressing externally viewable surfaces of masonry blocks used to construct mortarless retaining walls.

Retaining walls are widely used in a variety of landscaping applications. Typically, they are used to maximize or create level areas and also to reduce erosion and slumping. They may also be used in a purely decorative manner. In the past, retaining wall construction was labor intensive and often required the skills of trained tradespeople such as masons and carpenters. More recently, retaining wall construction has become significantly simplified with the introduction of self-aligning, modular molded blocks of concrete that may be stacked in vertical or offset courses without the use of mortar or any special skills. These blocks are available in a variety of shapes and sizes and a great many of them even allow a retaining wall to be curved or sinuous, so that it may be constructed circumjacent a tree, or parallel to a meandering pathway, for example.

Initially, these blocks were available in a limited number of sizes, shapes and textures. However, as the aforementioned blocks have become more and more popular, a greater variety of blocks of different styles have become available to the consumer. A particular style of block that is increasing in popularity is the rustic or weathered look. Rustic or weathered look blocks are desirable for several reasons. First, they convey the impression of craftsmanship that is nowadays frequently absent. Second, their time worn appearance conveys a sense of security and stability. And third, they are visually pleasing to an observer. With rustic or weathered blocks, it is possible to form structures that give the impression that they were constructed by artisans of a bygone era. These styles of blocks are particularly useful in restorative or rehabilitation work, or where certain stylistic and structural standards must be maintained.

A variety of approaches have been used to create rustic blocks. The most elementary and straightforward approach is to take a molded block and hand dress or roughen the surface. This approach has several drawbacks that are difficult to overcome. One, it significantly adds to the cost of the product because it is necessary to hire a person (or more likely, a crew of people) to perform this additional task. And, it may also be necessary to train or otherwise educate a person to perform such a task. Two, it increases the time necessary to produce such a product because hand dressing requires additional, time-consuming steps. Whether at the factory or at a job-site, each block must now be moved to a work station where it is hand dressed prior to use.

Since it is prohibitively expensive to hand dress block, alternative approaches to forming rustic blocks have been attempted. One approach has been to provide a patterned mold that is able to simulate a rustic surface. This approach has its drawbacks. One, It takes time and efforts to create and fabricate a mold. Two, the process of molding a block includes additional time consuming steps. Three, the process is limited to the formation of a particular style of block. And while it eliminates the step of hand dressing, a user is more-or-less stuck with the product as it comes from the mold. Any modification thereafter would defeat the purpose of such a block. And four, the molded surface does not have the appearance of hand dressing that is desired by the increasingly discerning and sophisticated customer.

Another approach is to take a molded block and place it in a rotatable container that tumbles it about (preferably, with other blocks or suitable material). This approach is much more cost effective and efficient that that of hand dressing each block. And, as with hand dressed blocks, each block so produced has a distinctive character. This approach, however, has a major drawback. The problem is that as a block is being tumbled, all of the exterior surfaces are being ground down. While this is a desirable result where the externally viewable surface of the block is concerned, it is an undesirable result for the remaining exterior surfaces of the block, particularly at the sides where the ability of adjacent blocks to be positioned flush against each other in a sealing relation may be compromised. Thus, instead of having linear side surfaces in sealing relation between adjacent blocks, there are now jagged side surfaces that form gaps or spaces therebetween. These gaps allow back-fill material to filter therethrough and accumulate in front of the structure. This is often exacerbated by rainfall that mixes with and transports particulate matter through the gaps, which may stain or otherwise leave residue on lower courses blocks that detracts from the overall appearance of the structure.

Another approach is to form them during the manufacturing process. This is most often accomplished by casting two blocks together in a single mold and splitting them apart along a predetermined plane. This creates two blocks, each with a front face that has the appearance of a natural split rock. A drawback with this approach is that blocks produced in this manner, while attractive, do not convey the impression that they were entirely hand worked. At best, they suggest that the blocks were broken away from a parent material and then machine dressed to predetermined dimensions. Thus, they have tight, thin, straight joints and, when assembled together, give the impression of a unitary structure having a textured surface.

Efforts to create a more realistic looking rustic block based on the aforementioned split-face block have taken several approaches. One approach is to hand dress selected portions of a block. This approach is less labor intensive than hand dressing the entire surface of a block as previously mentioned, but it still has the same aforementioned drawbacks—though to a lesser degree. One, it significantly adds to the cost of the product because it is necessary to hire a person (or more likely, a crew of people) to perform this additional task. And, it may also be necessary to train or otherwise educate a person to perform such a task. Two, it increases the time necessary to produce such a product because hand dressing requires additional, time-consuming steps. Whether at the factory or at a job-site, each block must now be moved to a work station where it is hand dressed prior to use.

Yet another approach uses flails to modify the externally viewable surfaces of blocks. Typically, the flails comprise short sections of chain one end of which is affixed about the perimeter of a rotatable element, the other end of which is attached to a steel head. In operation, the steel heads of the flails strike the entire front surface of a block as they are swung about by the rotatable element. While the flails produce acceptable results, there are several drawbacks. One, in order for the flails to operate at maximum efficiency, they must be swung about at a high rotational speed. This presents potentially dangerous condition, for if a flail were to break loose from the rotating element, they could easily injure people within the vicinity. Two, single or multiple links of a chain could break loose. This means that the flails must be inspected periodically to ensure that there are no cracks or damaged links that may lead to failure. The result is down time and loss of production. Three, as the flails strike a surface, they tend to crush or blast away the material away and form large amounts of dust. This presents health concerns such as ingestion, inhalation and sanitation. Moreover, such dust may create dangerous operating conditions by reducing visibility within the immediate vicinity or by settling upon equipment and obscuring essential components such as gauges or warning stickers. And, airborne dust also creates the potential for explosions initiated by sparks or electrical discharges. Four, flails are noisy, and people in the vicinity may be adversely affected by prolonged exposure to the noise associated with operation of such a device—even with the provision of ear protection.

There is a need for a masonry block that, when assembled together with other masonry blocks to form a structure, creates the impression that craftsmen using hand tools constructed the structure. There is also a need for a masonry block that may have marginal areas of its externally viewable surface dressed and still be able to be combined with other masonry blocks to form joints that effectively prevent passage of particulate matter therebetween.

There is also a need for an apparatus that is able to dress externally viewable surfaces of blocks without altering the remaining surfaces of the blocks, and do so in a manner that minimizes the formation of undue amounts of dust. There is yet another need for an apparatus that may be adjusted to accommodate masonry blocks having different dimensions, and which may be configured and arranged to dress only marginal areas of externally viewable surfaces of masonry blocks. There is yet another need for an apparatus that is able to dress a plurality of masonry blocks in an expedient and efficient manner.

And, there is a need for a method by which rustic masonry blocks may be fabricated.

SUMMARY OF THE INVENTION

The present invention comprises an apparatus for working externally viewable surfaces of masonry blocks in such a manner so that they appear to have been hand dressed. For purposes of this application, the term masonry block (or block) is intended to include any naturally occurring material, manmade material, molded cementitious block, natural and artificial stone or like material that may be used for buildings, indoor walls, partitions, facades, retaining walls, walkways, or other similar structures, with or without mortar. Preferably, the apparatus comprises a first station and a second station. The first station includes a pair of cylindrically shaped, rotatable chippers with each chipper having a rotational axis and a plurality of outwardly extending teeth randomly disposed thereabout. The chippers are adjustably arranged so that the rotational axes are parallel to and spaced apart from each other so that the outwardly extending teeth of the chippers do not interfere with each other during operation of the first station.

The first station also includes an adjustable block support that is positioned adjacent the chippers; preferably in an orthogonal relation relative to the rotational axes of the chippers. The support is configured and arranged to permit constrained movement of a block towards and away from the rotatable chippers to enable opposing, marginal areas of the externally viewable surface of a block to be simultaneously worked. In operation, the teeth of the chippers work or knap the opposing marginal areas of the externally viewable surface by percussively impacting and fracturing a block in a random manner. This produces an erose or jagged surface that is indicative of a rustic style block. For purposes of this application the term tooth (and its plural form, teeth) is intended to include any protrusion, projection, tooling or other such structure capable of dressing or knapping portions of a masonry block. Also for purposes of this application the term marginal area includes not only the areas adjacent the periphery of the externally viewable surface of a block but also other marginal areas form, for example, at the intersection formed by facets in a block having a non-planar externally viewable surface.

The second station includes another pair of cylindrically shaped, rotatable chippers with each chipper having a rotational axis and a plurality of outwardly extending teeth randomly disposed thereabout. As with the pair of chippers at the first station, the chippers in the second station are adjustably arranged so that the rotational axes are parallel to and spaced apart from each other so that the outwardly extending teeth of the chippers do not interfere with each other during operation.

The second station also includes an adjustable block support. As with the support at the first station, this support is positioned adjacent the chippers. However, instead of being positioned orthogonal to the rotational axes of the chippers as with the first station, this support is positioned so that it is collaterally aligned with and between the rotational axes of the chippers at the second station. The support is configured and arranged to permit constrained movement of a block collaterally with respect to the rotational axes of the rotatable chippers to enable opposing, marginal areas of the externally viewable surface of a block to be simultaneously worked. In operation, the teeth of the chippers work or knap the opposing marginal areas of the externally viewable surface by percussively impacting and fracturing a block in a random manner. This produces an erose or jagged surface that is indicative of a rustic style block. Thus, by using the first and second stations, it is possible to dress a plurality of marginal areas of an externally viewable surface of a masonry block in an efficient and expedient manner.

The apparatus may be used with a wide variety of preformed masonry blocks having a wide variety of sizes and surface textures. With the apparatus, it is possible to work a single or multiple areas of an exterior surface. For example, it is possible to work only the vertical margins of a block. Or, it is possible to work only the horizontal margins of a block. Or, it is even possible to work only one vertical margin and one horizontal margin. In that vein, it is envisioned that the apparatus may even work marginal areas that are not at the periphery of an externally viewable surface.

Preferably, the apparatus is used in conjunction with masonry blocks that have a split-face or roughened surface, so that the entire externally viewable surface of the dressed block appears rustic.

It is an object of the present invention to provide an apparatus that is able to dress marginal areas of a masonry block.

Another object of the present invention is to provide a method by which a masonry block may be dressed.

Yet another object of the invention is to form erose marginal areas that simulate hand dressing.

It is another object of the present invention to increase the speed at which rustic masonry blocks may be fabricated by providing a plurality of chipper units.

It is yet another object of the invention to provide a masonry block that, after dressing, is able to substantially contact an adjacent masonry block and effectively prevent particulate matter from passing therebetween.

A feature of the present invention is the use of chipper having a body with a rotational axis, about which a plurality of teeth are randomly disposed.

Another feature of the invention is that the components of the apparatus may be adjusted to provide different knapping depths, or to accommodate differently sized blocks.

An advantage of the present invention is that the randomly disposed teeth impact a marginal area being worked at a relatively slow speed.

Another advantage of the present invention is that formation of dust during the knapping process is minimized.

An advantage of the present invention is that the apparatus is able to accommodate a variety of differently shaped blocks.

Another advantage of the invention is that a plurality of dressed blocks may be dressed in an expedient and efficient manner.

These and other objectives, features and advantages of the invention will appear more fully from the following description, made in conjunction with the accompanying drawings wherein like reference characters refer to the same or similar parts throughout the several views. And, although the disclosure hereof is detailed and exact to enable those skilled in the art to practice the invention, the physical embodiments herein disclosed merely exemplify the invention, which may be embodied in other specific structure. While the preferred embodiment has been described, the details may be changed without departing from the invention, which is defined by the claims.

DETAILED DESCRIPTION

With reference toFIG. 1a block dressing apparatus10and an associated block100are depicted schematically, with the block100progressing through first and second stations14,16of the apparatus10. Beginning at the first station14, a block100that is to be dressed is positioned so that the externally viewable surface is in confronting relation to the chippers20,30of the first station14. The block100is then moved towards the chippers20,30so that the teeth of the chippers knap or otherwise work marginal areas (in this depiction, the marginal areas are at opposing transverse peripheral surfaces). The block is then moved away from the chippers20,30. If other marginal areas are to be dressed, the block100is moved to the second station16. There, the block100is moved in a collateral direction relative to a second set of chippers60,70which also knap or otherwise work the other marginal areas (in this depiction, the marginal areas are along opposing longitudinal peripheral surfaces) and complete the dressing process.

Generally, the first station14comprises first and second chippers20,30and a support50. More specifically, the first chipper20includes a body22with a rotational axis24and a plurality of outwardly extending teeth26randomly disposed thereabout. The second chipper30includes a body32with a rotational axis34and a plurality of outwardly extending teeth36randomly disposed thereabout. The first and chipper bodies22,32are cylindrically shaped and have a diameter of around 1.0-4.0 inches (2.54-10.00 cm), respectively, and a preferred diameter of around 2.0-3.0 inches (5.00-7.50 cm). The first and second chippers20,30may be operatively connected to separate motive sources, or preferably a single motive source such as a hydraulic motor and a drive chain (not shown) that rotate the chippers20,30at a rate of around 100-500 revolutions per minute (rpm) and preferably around 200-375 rpm. As will be appreciated, the rotational directions of the first and second chippers20,30are chosen to so that the chippers work in opposition to each other.

A support50is positioned adjacent the first and second chippers20,30in an orthogonal position relative to the rotational axes of the first and second chippers20,30. The support50is configured to allow a block to move in a constrained manner. This may be done with the provision of adjustable fences52,54and an adjustable stop56. The stop56may be provided with a biasing element58that assists in disengaging a block from contact with the chippers20,30. While this embodiment uses fences and a stop to direct the movement of a block with respect to the chippers20,30other arrangements are possible. For example, the support50may be provided with a channel or aperture (not shown) that is configured to receive an indexing projection of a block (See, for example, the projections depicted in the blocks ofFIGS. 8 and 10) thus eliminating the need for auxiliary fences52,54and stop56. Or, the support itself may be used to move a block into engagement with the chippers.

As with the first station, the second station16generally comprises a pair of third and fourth chippers60,70and a support90. More specifically, the third chipper60includes a body62with a rotational axis64and a plurality of outwardly extending teeth66randomly disposed thereabout. The fourth chipper70includes a body72with a rotational axis74and a plurality of outwardly extending teeth76randomly disposed thereabout. The third and fourth62,72are also cylindrically shaped. They are larger in diameter than the first and second chippers, however, and have a diameter of around 4.0-6.0 inches (10.00-15.25 cm), respectively, and a preferred diameter of around 4.5-5.5 inches (11.40-14.00 cm). The third and fourth60,70are also operatively to motive sources, or preferably connected to a motive source such as a hydraulic motor and a drive chain (not shown) that rotate the chippers60,70at a rate of around 10-200 revolutions per minute (rpm) and preferably around 50-150 rpm. As will be appreciated, the rotational directions of the first and second chippers60,70are chosen to so that the chippers work in opposition to each other so that the forces of impact tend to cancel each other out.

A support90is positioned adjacent the third and fourth chippers60,70collaterally and between the rotational axes64,74of third and fourth chippers60,70. The support90is configured to allow a block to move in a constrained manner. This may be done with the provision of an adjustable fence92(See,FIG. 3). While this embodiment uses a fence to limit the movement of a block with respect to the chippers60,70other arrangements are possible. For example, the support90may be provided with a channel or aperture (not shown) that is configured to receive an indexing projection of a block thus eliminating the need for auxiliary fence92.

With reference toFIGS. 2 and 3, a block100to be worked is brought to the first station14and positioned on the support50so that it will fit between the fences52,54and so that the externally viewable surface faces the chippers20,30. The block100is then advanced towards the chippers20,30and stop56, opposing marginal areas of the block100will be introduced into the working fields28,38of the chipper teeth26,36, respectively, and be knapped or dressed. When the block100contacts the stop56, dressing of the opposing marginal areas is essentially complete. The block100is then withdrawn from engagement with the chippers20,30with the assistance of a biasing element58. After the block is disengaged from the chippers20,30of the first station14, the block100is brought to the second station16where it is positioned on the support90so that it is offset with respect to the third and fourth chippers60,70and collaterally aligned with the rotational axes64,74thereof. The block100is then advanced in a direction parallel to the chippers60,70so that a second set of opposing marginal areas of the block100will be introduced into the working fields68,78of the chipper teeth66,76, respectively, and be knapped or dressed. As the block100moves past the chippers60,70the fence92maintains the distance and orientation between the block100and the chippers60,70and ensures that the correct amount of material will be knapped from the block.

As will be appreciated, the speed at which the block100is moved relative to the chippers60,70is an additional variable that contributes to the distinctive surfaces that may be achieved with the apparatus. For example, if the block100is moved rapidly relative to the chippers, the chipper teeth will impact the block a fewer number of times than if the block100is moved slowly relative to the chippers.

Referring toFIGS. 4 and 5, the teeth of the first, second third and fourth chippers20,30,60,70are substantially the same. Generally, each tooth (26,36,66,76of chippers20,30,60,70, respectively) comprises a base94and a protrusion96that extends therefrom, with the protrusion including an impacting surface98. As can be seen inFIG. 4, the tooth extends in a radial direction with respect to the rotational axis of the chipper, and is oriented so that the impacting surface98faces in the direction of rotation of the particular chipper to which it is attached. Turning toFIG. 5, the random arrangement of the outwardly extending teeth may be seen. Note that the teeth are randomly arranged with respect to the rotational axis and the length of each chipper (See,FIG. 1). Randomly arranged teeth are preferred because they are able to reproduce the erose or jagged surfaces indicative of hand dressing. And, when two or more chippers are used, this feature assures that the surfaces worked by different chippers will not appear the same, thus enhancing the rustic look. While it has been determined that commercially available replacement teeth for stump grinding machines work quite well with the chippers of the present invention, other teeth may be used. Preferably, each tooth is around 1.3-3.5 inches (4.0-10.0 cm.) in length, although it is understood that the teeth may have edifferent lengths and different impacting surface profiles, if desired. The teeth may be attached to the chipper body in a conventional manner, such as welding, or bolting. Or, alternatively, the teeth may be integral to the chippers.

In conjunction with the chippers, it is envisioned that the block dressing apparatus may be provided with static or movable brush-like elements (not shown) that finish a block by blending impact marks left by the teeth with the rest of the externally viewable surface. Alternatively, the chipper bodies themselves may include brush elements thereon (also not shown) so that they are able to dress and finish a portion of an externally viewable surface of a block.

Referring now toFIGS. 6,7and8, a typical, representative masonry block100that may be used in conjunction with the block dressing apparatus10is shown prior to, and after dressing its marginal areas. Generally, the block100has two parts, a rear extension104and a front member104. Since the rear extension102does not involve the inventive concepts in this disclosure, it will not be discussed in great detail. In addition to the rear extension102and the front member104, the block100includes a top106with a block contacting surface108, a bottom110with a block contacting surface112, and opposing sides122,124. Typically, the bottom110may include two projections114,118with indexing surfaces116,120, respectively, that are used to align and position as they are set in courses.

Each side122,124includes block contacting surfaces126,128, and130,132, respectively. And, each side122,124also includes splitting or fracture relief notches134,136, and138,140, respectively. The block100also includes an externally viewable surface142having a central area144(generally indicated by a dashed line) with opposing marginal areas146,148and150,152. It will be appreciated that the central area144will vary depending upon the particular configuration of the block and the extent to which the block is to be dressed. Referring toFIG. 6, the block100, as depicted, has not been dressed by the apparatus10. As can be seen, the externally viewable surface142includes marginal areas146,148,150and152that form well defined angles with adjacent block contacting surfaces128,132,108,112, respectively.

The block depicted inFIGS. 7 and 8, has had its marginal areas146,148,150and152dressed, and no longer has the well defined angles formed by the marginal surfaces and the block contacting surfaces. When the marginal areas of a block are dressed in the rustic style, the block contacting surfaces are reduced in size and the ability of adjacent blocks to form an effective seal could be compromised. That is, the chippers of the apparatus could remove too much material. This is prevented by the notches136,140that separate block contacting surfaces126,128, and130,132, respectively. Normally, after the dressing operation, there is enough of the block contacting surfaces128,132left to form an effective seal with block contacting surfaces of adjacent blocks. If the block is knapped too hard, and the block contacting surfaces128,132are compromised, the block contacting surfaces126,130are available to form effective seals with adjacent blocks. This is possible because the notches136,140isolate the block contacting surfaces and prevent cracks from propagating thereby. Thus, the block has a plurality of block contacting surfaces that may form a plurality of effective seals with adjacent blocks.

Referring toFIG. 9, the importance of relief notches and block contacting surfaces126,128,130and132is illustrated. Here, fill material between adjacent blocks is prevented from passing therebetween by the effective seals formed by block contacting surfaces126,130, and128,132, respectively. It will be appreciated that an effective seal between adjacent blocks may be achieved even if the sealing ability between block contacting surfaces128and132is compromised due to excessive knapping or damage.

Referring now toFIG. 10, another representative masonry block160that may be used in conjunction with the block dressing apparatus10is shown after dressing some of its marginal areas. As with the previously discussed block100, this block160has two parts, a rear extension162and a front member164. Since the rear extension162also does not involve the inventive concepts in this disclosure, it will not be discussed in great detail. In addition to the rear extension162and the front member164, the block160includes a top166with a block contacting surface168, a bottom170with a block contacting surface172, and opposing sides182,184. Typically, the bottom170may include two projections174,178with indexing surfaces176,180, respectively, that are used to align and position as they are set in courses.

Each side182,184includes block contacting surfaces186,188, and190,192, respectively. And, each side182,184also includes splitting or fracture relief notches194,196, and198,200, respectively. The block160includes an externally viewable surface202having a central area204(generally indicated by a dashed line) with opposing marginal areas206,208and210,212. As with the aforementioned central area144of block100, the central area204of this block160will vary depending upon the particular configuration of the block and the extent to which the block is to be dressed.

As depicted, the block(s)160have had their marginal areas206,208dressed, and no longer have the well defined angles formed by the marginal surfaces and the block contacting surfaces. As with block100, the block160has a plurality of effective seals formed by the block contacting surfaces of adjacent blocks. That is, an effective seal is formed by block contacting surfaces186and190, and another effective seal is formed by block contacting surfaces188,192. The block160is also provided with relief notches196,200that isolate the block contacting surfaces186,188, and190,192, respectively, and prevent undesirable crack propagation.

Referring toFIG. 11, a wall220is depicted with three diagonal columns of blocks. The leftmost diagonal column222comprises blocks that have a substantially smooth central area and dressed marginal areas, similar to the dressed block depicted inFIG. 7. The middle diagonal column224comprises blocks that have a roughened or textured surface and dressed marginal areas. And, the rightmost diagonal column226comprises blocks that have a substantially smooth central area and only the sides dressed, similar to the block depicted inFIG. 10. It is understood that the wall220is merely an example of the types of blocks and dressing that may be used in one type of construction, and that other blocks and dressing may be used in other structures.

A brief description of a preferred method of dressing a plurality of marginal areas of an externally viewable surface of a masonry block will now be discussed. Initially, a person would first start by determining the environment and structure in which the block is to be used—an outdoor retaining wall, for example. Then, an appropriately configured, preformed block would be selected and the areas to be worked determined. The components of the first and second stations of the apparatus would then be adjusted, if need be, to reflect the dimensional characteristics of the preformed block and the areas of the externally viewable surface to be worked. For example, it may be necessary to lengthen or shorten the distance between the rotational axes of parallel chippers at the first and second stations in order to bring the chippers into the desired confronting relation to marginal areas of an externally viewable surface to be worked. Similarly, it may also be necessary to adjust the guide fences, stop, and block supports.

Dressing a block using the apparatus of the present invention may now proceed. First, the block is moved to the first station and positioned so that the externally viewable surface confronts the first pair of chippers. The block is then moved in a constrained manner towards the chippers until it reaches a stop. As the externally viewable surface of the block approaches the stop, the marginal areas enter the working field of the teeth, which dress the surface. Dressing of these marginal areas is essentially complete at the point where the externally viewable surface of the block contacts the stop. After the block has reaches the stop, the now partially dressed block is withdrawn from engagement with the chippers of the first station and moved to the second station.

At the second station, the block is positioned parallel to and laterally offset with respect to the rotational axes of the second pair of chippers. The position of the block is then adjusted so that the marginal areas of the externally viewable surface that are to be worked will fall within the working fields described by the rotating teeth of the chippers. After making the necessary adjustments, the block is then moved parallel to the rotational axes of the second pair of chippers in a constrained manner. As the marginal areas of the externally viewable surface enter the working fields of the chipper teeth, they are dressed, and after the block passes the second pair of chippers, the marginal areas of the block are now completely dressed.

It will be appreciated that there are ways other than the preferred method of dressing a masonry block. For example, there could be separate stations where each marginal area could be dressed separately. Or there could be one station where all of the work is done. In that vein, it will also be appreciated that the block could be relatively stationary and the tooling is movable with respect thereto.