Self-propelled apparatus for setting cemetery markers and the like

A wheeled, self-propelled apparatus has a percussion tool or hammer mounted on its forward end and an impact transmitting means carried on the tractor below the hammer. The impact transmitting means is adapted to be mounted to transmit repeated impacts from the hammer to a cemetery marker until the latter is flush with the ground surface where it will not interfere with ground maintenance, such as lawnmowing and the like.

The present invention relates generally to a method and apparatus for 
reducing the cost of maintaining a cemetery and, more particularly, to a 
self-propelled percussion unit, and method of using same, especially 
adapted for driving previously installed cemetery markers into the ground 
so that grass can be cut with a mower running over the cemetery markers 
with the mower blade operating at a normal cutting height. 
In recent years, the cost in maintaining cemeteries has increased 
dramatically to the point where cemetery maintenance is a real problem. 
Where cemetery markers were installed projecting above the ground, a 
self-propelled mower cannot pass over the raised marker when the mower 
blade is operating in a normal cutting position. The cost to hand trim 
markers is becoming prohibitive, and mowing costs are substantial if a 
mower must maneuver around protruding markers. The problem has become so 
severe that a large number of cemeteries no longer permit a marker to be 
installed projecting above the ground where it will interfere with a 
self-propelled mower. Although grass immediately around a grave marker can 
be controlled by grass killers and the like, this is expensive and still 
requires that the mower negotiate around the raised markers. 
The increase in maintenance cost caused by the raised markers has in some 
cases been sufficient to justify cemetery workers digging up markers and 
their foundations, deepening the excavation and then reinstalling the 
foundation and the marker flush with the ground. This manual operation is 
time consuming and expensive, and the cost to manually relocate the marker 
flush with the ground can easily be on the order of $10 to $20 per marker. 
This cost is almost prohibitive with large older cemeteries having 
literally thousands of raised cemetery markers. 
A principal object of the present invention is to reduce the cost in 
maintaining cemeteries that presently have cemetery markers projecting 
above the ground sufficiently to interfere with a self-propelled mower 
passing over the marker while it is cutting grass. 
A further object of the present invention is to provide a self-propelled 
percussion unit having a specially constructed impact transmitting 
arrangement that rapidly and effectively drives cemetery makers flush with 
the ground at relatively low cost, without damaging the marker, and in a 
relatively short time compared to prior manual marker relocation 
techniques; that is usable with markers of various different 
configurations; and/or that can be constructed by relatively simple 
modification of existing percussion units presently used for other 
purposes. 
A further object of the present invention is to provide a method for 
relocating cemetery markers of the type referred to above in a manner that 
is simple, usable with a wide variety of marker configurations, relatively 
low in cost by comparison to prior manual techniques, that will not damage 
the markers and/or that can be readily implemented by relatively simple 
modification of existing percussion units presently used for the other 
purposes.

Referring to the drawings in general, a hammer 10 is carried at the lower 
end of a heavy weight 12 which is longitudinally reciprocally mounted on a 
track or tower 14 comprising first and second laterally spaced inwardly 
tapering track members 16, 17 slidably received in corresponding channels 
in the weight side edges. Tower 14 is carried on tracks 18,19 for 
transverse positioning relative to a frame 20 which, in turn, is carried 
by a hinge bracket 21 for pivotal movement in a vertical plane. Track 14 
is additionally carried for pivotal adjustment in the direction of the 
plane of track members 16, 17 by means not shown between track 14 and 
frame 20. Bracket 21 is carried by self-propelled wheel vehicle 22 for 
translocation of the apparatus over the earth surface 24. A hydraulic ram 
25 is carried by a support bracket 26 on vehicle 22 and is powered by the 
vehicle engine (not shown) to lift hammer 10 and weight 12 by means of a 
cable 27 trained over suitable idler pulleys 28. Additionally, lateral 
adjustment of track 14 with respect to frame 20 and pivotal adjustment 
with respect to bracket 21 are powered by hydraulic rams (not shown). The 
various hydraulic systems, including ram 25, are interconnected by hoses 
29 and are selectively controlled by an operator of vehicle 22, as by a 
control handle 30. 
With the exeception of modifications to be hereinafter described, the 
arrangement and contruction thus far set forth may be substantially 
identical to that described and disclosed in U.S. Pat. No. 3,172,483, 
granted Mar. 9, 1965, which patent is incorporated herein by reference. 
Self-propelled percussion units of this general type are well known for a 
multiplicity of uses, for example, tamping fills, cutting and breaking 
pavement, driving posts and pilings, and the like, and are available from 
several manufacturers including the Arrow Manufacturing Company of Denver, 
Colo. to which the aforementioned U.S. Pat. No. 3,172,483 was assigned. 
When an operator initially energizes ram 25, cable 27 is retracted to move 
weight 12 and hammer 10 upwardly on opposed track members 16,17 to a 
raised position, generally anywhere from an inch or so up to several feet, 
for example eight feet, above the earth surface. At this point, the 
hydraulic system releases weight 12 so that it falls freely by force of 
gravity to develop a high impact force at hammer 10. Typically, weight 12 
might be on the order of one thousand pounds or more. 
In conventional percussion units, the controls of the hydraulic systems are 
arranged such that, once the operator initiates the operation, the 
cylinder will be cycled repeatedly until the operator deactivates the 
control. According to one aspect of the present invention, the hydraulic 
control is modified so that the weight 12 and hammer 10 are raised and 
dropped only once each time the operator actuates the control, as by 
control handle 30. This is a very simple modification that can be 
accomplished by by-passing the automatic sequencing valve. Aside from this 
minor modification and the modification of the hammer as will be 
described, the above described percussion unit may be otherwise 
substantially identical to the aforementioned commercially available 
units. 
According to a first aspect of the present invention, the commercially 
available percussion unit is modified by adding an impact transmitting 
member 34 that can be raised and lowered independently of hammer 10 and 
can be positioned below hammer 10 on top of a cemetery grave marker 36. 
More particularly, the member 34 comprises a generally rectangular frame 
38 having a pair of side or end plates 40, front and rear plates 42, 43 
and top plate 44. The plates are securely welded together to form a 
downwardly opening cavity 46 in which wood timbers 48 are mounted so as to 
fill the cavity and project below plates 41, 42, 43 and form a flat, lower 
cushion surface 50 for engaging directly against marker 36. The frame 38 
and particularly the top plate 44 must be rigid, strong and hard to 
withstand repeated severe impact forces from hammer 10. In one embodiment 
of the present invention, top plate 44 was a 2-inch thick steel plate, 26 
inches in depth (in a direction longitudinally of the wheeled tractor 22) 
and 22 inches wide (in a direction transversely of the tractor 22). Plates 
40, 42, 43 are formed of 1-inch thick steel plate, 4 inches tall so that 
the cavity 46 can accommodate two 8".times.10".times.24" wood timbers of 
generally rectangular cross section with the upper surface of the timbers 
bottomed against the lower surface of top plate 44. Although the timbers 
can be maintained in the cavity by making them slightly oversized and 
driving them in place, preferably they are held in place on the frame 38 
by a pair of bolts 52 that extend transversely through the timbers and the 
side plates 40. Although various types of wood timbers could be used, it 
has been found that elm timbers operate very effectively since, although 
very soft in comparison to steel, elm is a relatively hard wood that will 
withstand repeated impact against the marker without splitting and 
splintering. 
Frame 38 is connected to a pair of triangular hanger plates 54 located, 
respectively, at opposite sides of tower 14 by means of four tension 
springs 56, 57, 58, 59 at each plate 54 as best shown in FIG. 2. The front 
spring 56 is fastened at its upper end to the front of plate 54 by rings 
60 and at its lower end via ring 62 to a laterally extending lug 64 on the 
front plate 42. The rear spring 59 is similarly fastened to the rear of 
hanger plate 54 and the rear wall 43. The center two springs 57, 58 are 
connected at their top ends, respectively, to the front and rear of hanger 
plate 54 and at their lower ends to a lug 66 welded on the sidewall 40 
midway between the front and rear walls. An identical spring arrangement 
is provided at the opposite side of frame 38. As will later be more 
apparent, the spring arrangement insures that the frame can maintain a 
horizontal position when placed against the top surface of markers having 
different configurations and also permits the frame to move downwardly 
against the tension of the springs when the plate 44 is impacted by hammer 
10. 
The hanger plate 54 at the left side of tower 14 as viewed in FIG. 1 is 
pivotally connected at 70 to the lower end of a cable 72 which passes 
upwardly in a straight run over an idler pulley 74 with the cable 
continuing upwardly and over a pair of pulleys 76, 78 at the top of tower 
14, and then downwardly around a further pulley 80 (FIG. 2) and then back 
upwardly where it is fastened at its other end to the piston 82 of a 
hydraulic cylinder 84 mounted on the hammer tower 14. Cylinder 84 is 
controlled by a hand operated valve 86 mounted on a front frame 90 carried 
on tower 14. Suitable hydraulic interconnections can be provided as 
illustrated by the hydraulic lines 92 interconnecting the cylinder 84, the 
control valve 86 and the hydraulic pressure system (not shown) so that a 
worker can actuate cylinder 84 while he is standing in front of or at the 
side of tower 14 to raise and lower frame 38. In a similar fashion, the 
hanger plate 54 at the right of tower 14 as viewed in FIG. 1 is connected 
at 94 to the lower end of a cable 96 that passes upwardly between an idler 
pulley 98 and a second groove on the pulley 80 with the upper end of cable 
96 being connected to piston 82. With this arrangement, when piston 82 is 
actuated, cables 72, 96 move in unison to raise and lower frame 38 while 
the lower surface 50 of the timbers stays in substantially a horizontal 
plane. 
Referring now to FIGS. 1, 2 and 4, as indicated earlier, the hammer portion 
of the commercially available percussion units has been modified slightly 
according to the present invention to better withstand repeated battering 
against the top plate 44 of the frame 38. The weight 12 is fastened at its 
lower end to a vertical column 100 that, in turn, has its lower end welded 
in a 2-inch thick steel block 102 with four reinforcing struts 104 being 
welded to column 100 and block 102 at positions equally spaced 
circumferentially about the column to further reinforce the hammer 10. 
Block 102 is, in turn, welded to a larger 2-inch thick steel block 108. 
Block 108 has a cross section in a horizontal plane of about 10 inches by 
10 inches and has a flat lower face 110 for impacting against the top face 
44 on the frame 38. Since the horizontal area of block 108 is 
substantially smaller than the area of plate 44, frame 38 can be 
manipulated so that hammer 10 strikes plate 44 at selected locations. On 
the other hand, plate 44 distributes the concentrated impact of hammer 10 
over larger areas for impacting marker 36. In this regard, the area of 
timber surface 50 is slightly larger than a typical cemetery marker. 
Also mounted on frame 90 slightly forward of the tower 14 is an electric 
motor-driven wench 120 having a cable 122 that is pivotally fastened at 
124 on a lug 126 welded on the front plate 42. A pair of curved guide 
rails 130 are mounted at their lower end on tower 14 and at their upper 
end on frame 90 so as to project slightly forward of the hammer 10 and 
guide the frame 38 forwardly when it is raised upwardly by retracting 
cable 122. As shown in FIG. 3, the frame 38 can be raised completely out 
of the way of hammer 10 as may be required during travel of tractor 22 or 
so that hammer 10 can be used for other purposes. With some lightweight 
markers such as sandstone, limestone or deteriorated markers, or in other 
situations justifying such procedure in the opinion of the operator, the 
marker can be removed and the foundation 142 driven down with hammer 10 
and then the stone replaced. Additionally, cable 122 can be used to 
slightly tilt the frame 38 if required for driving a particular type of 
cemetery marker. 
A further electric wench 130 is also mounted on the frame 90 by means of 
struts 132 which are pivotally connected to the frame 90 at 134. A hook 
136 is fastened at the lower end of a cable 138 of wench 130. In working 
with cemetery markers, it is frequently convenient to have a separate 
power-driven wench that can be used to assist the workman in dislocating, 
reorienting or even moving the marker as illustrated generally in broken 
lines in FIG. 2. 
In using the self-propelled unit of the present invention, the tractor 22 
is driven to the site of a marker 36 (FIGS. 1, 6 and 7) and positioned so 
that the hammer 10 is located directly above the center of the top surface 
140 of the marker. Usually, the markers will be in a row extending the 
direction of travel of tractor 22 so that the long dimension of the marker 
36 corresponds to the long dimension of frame 38 and tractor 22 straddles 
the row of markers. As illustrated schematically in FIG. 6, the marker 
extends or projects upwardly above the ground surface to a height where it 
would interfere with the passage of a lawn mower over the marker when the 
mower blade is operating at a normal cutting height. Flat rectangular 
markers of the type shown in FIG. 6 may be 12 inches by 24 inches, made of 
granite or marble, and typically project from 4 to 6 inches above the 
ground but could be as high as say 14 inches. As also illustrated in FIG. 
6, marker 36 is typically installed on top of a foundation 142 which would 
have to be dug up manually if one attempts to relocate the marker 36 
manually. The exact nature and arrangement of the foundation 142 varies 
greatly depending, in part, for example, on location, the practice at the 
cemetery involved, soil conditions and the year in which it was originally 
installed. The foundation might be a concrete pad 6 to 8 inches thick or, 
in some instances, it can be a concrete footing that extends a substantial 
depth of up to 42 inches, for example. 
When hammer 10 is positioned over marker 36 and frame 38 centered over the 
marker, and hence centered with respect to the hammer, the frame is 
lowered by lowering cables 72, 96 until the bottom surface 50 of timbers 
48 engages with the top surface 140 of the marker. In the preferred mode 
of operation, the cables are adjusted so that the springs 56-59 are in 
tension and supporting some of the weight of the frame and so that plate 
44 is horizontal or parallel with the bottom surface 110 of hammer block 
108. This insures that the hammer 10 will strike the top plate 44 over the 
entire interface therebetween; and if the marker is tipped slightly, the 
impact will tend to level the top surface of the marker as it is driven 
downwardly. After the frame is positioned, the operator on tractor 22 
actuates handle 30 to move hammer 10 and weight 12 to their raised 
position, at which point the weight is automatically released. The impact 
of hammer 10 on plate 44 is transmitted via timbers 48 to marker 36, 
driving it and foundation 142 downwardly into the ground. After each 
impact, the operator on the tractor will again actuate the cylinder 84 to 
raise the weight 12 and hammer 10 and repeatedly impact frame 38 and 
marker 36 until the foundation and marker are driven downwardly to a level 
where the top surface 140 is substantially flush with the ground. 
A typical marker that might extend 4 to 6 inches above the ground can be 
pounded flush with the ground with one to five impacts by hammer 10 which 
will take only a matter of seconds or, at most, several minutes. The unit 
is preferably manned by an operator on tractor 22 to operate hammer 10 via 
cylinder 84 and a second workman standing in front or at the side of the 
percussion unit so that he can make sure that the frame 38 remains 
properly positioned as the marker is driven flush with the ground. The 
workman standing at the front of the unit can, via valve 86, progressively 
lower cables 72, 96 to maintain timbers 48 horizontal and in engagement 
with the marker and true to the hammer while keeping the springs 56-59 
slightly tensioned. As indicated earlier, if a marker is slightly tilted, 
by keeping the frame 38 horizontal, the impact will be concentrated at the 
high side of the marker and will, as the marker is driven into the ground, 
level the top surface of the marker. Where this is not fully accomplished, 
as the marker is driven downwardly, the operator on the tractor can change 
the vertical orientation of the tower 14 and the workman at the front of 
the percussion unit can maneuver the frame 38 so that the impact is 
transmitted directly to the high side of the marker. This technique is 
also useful where the terrain is not level and it is desired to have the 
top surface of the marker conform to the terrain. After one marker is 
pounded into the ground, tractor 22 is driven to the next marker and it is 
pounded into the ground in the manner described hereinabove. 
Referring to FIGS. 8, 9 and 10 which illustrate another type of cemetery 
marker 36' having an inclined top surface 140', the hook 136 and cables 
138 can be used to lift or raise the front edge of the marker 36 and tilt 
it backward to the position illustrated in FIG. 9. The workman can then 
center the tilted marker 36' and align it with other markers. With the 
marker tipped as shown in FIG. 9, the workman lowers the frame 38, while 
keeping it horizontal, and lets it rest on the top surface 140'. In most 
cases, the weight of the frame and the tension in springs 56-59 are such 
that marker 36' will stay in the tilted orientation as it is driven 
downwardly until the top surface 140' is substantially flush with the 
ground as illustrated in FIG. 10. When a marker is tipped as illustrated 
in FIGS. 8-10, the marker 36' and foundation 142' may crumble or fracture 
slightly at the interface therebetween. However, it has been found that 
this does not usually cause any visible damage to the marker once it is in 
place. It is usually desirable to back fill under the bottom face of a 
tipped marker 36' before it is driven to prevent settling. 
Although the operation of the percussion unit has been described 
hereinabove in two examples wherein the springs 56-59 at both sides of the 
frame 38 are preferably kept tensioned, it will be apparent that the 
principal purpose of the springs is to permit the workmen to keep the 
frame 38 horizontal and trued relative to the hammer 10, which, in turn, 
will tend to drive the high side of the marker downwardly, leveling the 
marker and insuring that the full force of the hammer 10 strikes the plate 
44 directly. This also minimizes stresses on hammer 10 and tends to reduce 
secondary impacts that might be caused by a wobble at the frame. In order 
to achieve these objectives, depending on the circumstances, it may be 
necessary or desirable to permit the springs, at least at one side of the 
frame, to relax. On the other hand, where the top surface of the marker is 
substantially level before it is driven, the marker could be driven with 
the springs slack. However, it is preferred to keep the springs 56-59 at 
least slightly tensioned since the springs also tend to prevent the frame 
38 from becoming misaligned with the marker. 
One of the more important aspects of the present invention is the 
recognition and implementation thereof that a percussion tool can 
effectively drive cemetery markers flush with the ground in a simple and 
effective manner without damage to the marker. Before the practicality of 
the present invention was established by extensive testing, it was not at 
all certain that markers could be driven by brute force without 
substantial damage, if not complete fracturing, of the marker. However, 
based on the experience of driving hundreds of markers, it is estimated 
that the breakage is perhaps about one percent or less. Breakage is more 
likely to occur with slant-faced markers such as that shown in FIGS. 8-10, 
particularly where the marker is high or the angle of the slant face is 
great. Generally, sandstone and limestone markers should be removed and 
the foundations driven separately. Breakage can be reduced by exploring 
the area under the marker and foundation with a long steel rod if the 
marker does not move with a couple of blows. If the foundation bottoms on 
a large buried object, such as a large rock or vault, it may then be 
necessary to reposition the marker manually; but this does not occur very 
often. 
Another important feature of the present invention is that the use of a 
wooden cushioning pad provided by timbers 48 eliminates scarring of face 
140 of the marker 36 which would, of course, be undesirable. Additionally, 
the cushioning effect of the soft wood distributes the impact force over 
the entire surface of the marker to minimize fracturing the marker. The 
construction described hereinabove has proved very effective in driving 
numerous different configurations of markers without scarring, fracturing 
or otherwise damaging the markers. 
Although various types of percussion tools capable of driving a hard blow 
could be used, a percussion tool having a heavy weight on the order of 
1000 pounds is preferred and can provide the necessary driving force for a 
wide variety of conditions. The specific height to which weight 12 is 
lifted and the number of impacts depends on a number of factors including 
soil types and soil conditions, principally moisture content. By way of 
further illustration, when driving a marker and its associated foundation 
in moist loam soil, weight 12 might be lifted only 1 to 4 inches and just 
slightly higher for sand, for example, 1 to 6 inches. In heavier soils, 
weight 12 might be lifted from 1 inch to 2 feet in the case of sandy clay 
and from 1 inch to 4 feet in the case of clay. Hence, generally speaking, 
the impact will be the equivalent of dropping a 1000-pound weight a 
distance in the range of from 4 inches to 2 feet. A lighter weight, for 
example, a 500-pound weight, raised a higher distance could be used; but 
the heavier 1000-pound weight is preferred to reduce bouncing and 
secondary impact between hammer 10 and plate 44 and between timbers 48 and 
marker 36. 
The present invention also contemplates mounting frame 38 on tower 14 by 
means other than a cable-spring suspension system. However, the 
cable-spring arrangement is preferred because it allows the operator 
flexibility is positioning frame 38 relative to the marker and hammer 10 
and it can absorb the shock associated with an impact without unnecessary 
stress on the suspension system. 
It is estimated that in areas of low labor costs, a marker can be driven 
into the ground using the method and apparatus of the present invention at 
a cost that would be equal to about the cost to trim the marker for a two 
or three year period. In higher labor cost areas, the markers can be 
driven flush with the ground with the present invention at approximately 
the same cost to hand trim the markers over one season. Of course, once 
the marker is driven flush with the ground, maintenance costs are reduced 
substantially since the cemetery can be kept neat appearing with 
self-propelled mowers that can pass over the markers with the cutting 
blade operating at a normal cutting height of say about 2 to 4 inches.