Abstract:
The present invention provides a method of producing split casted concrete blocks. The method comprises the steps of providing a production plate adapted to support one or more casted blocks. One or more of these blocks are casted on the production plate. A parting slot is formed on a top surface of each of the one or more blocks. The production plate is transported to a support surface of a block splitting machine. Each of the blocks is impacted with a pitching blade aligned with the parting slot of a respective one of the one or more casted blocks to form the split blocks on the production plate.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   This application is a divisional of application Ser. No: 11/159,187, filed Jun. 23, 2005 now U.S. Pat. No. 7,077,121. 

   TECHNICAL FIELD 
   The present invention relates to a method of producing split casted concrete blocks with a pitching blade which is automatically positioned precisely above a parting slot provided in a concrete casted block to be split. 
   BACKGROUND ART 
   Devices have been constructed for over one hundred years to split blocks by the use of wedges. For example, in U.S. Pat. No. 630,983 issued in 1899, there is described an apparatus for splitting stones wherein a stone is mounted on a support behind a stationary wedge and a second wedge is secured to a pendulum hammer wedge hinged by stirrups whereby to swing down the hammer wedge against the stone so that the wedge strikes the stone in substantially the same plane as the stationary wedge so that the stone is impacted with wedges from opposed surfaces thereof. Several other devices have also been developed and wherein the wedges are brought down against the stone at more precise locations by mounting wedges on displaceable supports which are displaced by a threaded rod to which is imparted rotation by rotating a wheel secured to the threaded rod. The force applied to the splitting wedge is that of the force applied on the wheel by a worker. All of these devices are slow, labor intensive, time-consuming and do not provide accurate splitting of stones thereby resulting in excessive material waste. Some of these are also dangerous to operate and can cause body injuries. 
   Paving stones are now casted from concrete and with some of these it is desirable to split the casted concrete stones whereby to form two stones with a split face whereby the split face is jaggered by exposing the aggregate and thereby closely resembles that of a natural stone. In order to split these stones they are casted with a parting slot on a face thereof whereby a splitting chisel or blade can be positioned therein and by the use of a hammer the stone is manually split. Some problems with this technique is that it is slow and the hammer blow is never of the same force and often it is necessary to impart two or more hammer blows to a chisel to split the stone as the stone resistance in the area of the parting line may vary depending on the aggregate distribution under the parting slot. Such techniques are also hazardous in that chips of stone may injure the person splitting the stone. They also result in some stone waste by improper splitting. 
   Another disadvantage is that the stones need to be transferred one at a time to a splitter and then back onto a pallet or storage plate. This is labour intensive, hazardous and costly. 
   SUMMARY OF INVENTION 
   There is therefore a need to provide a block splitter which substantially overcomes the above-mentioned disadvantages of the prior art. 
   It is a feature of the present invention to provide a block impact splitter which is fully automatic and which can split several pre-casted concrete stones at the same time and at a precise location and wherein the block impact splitter is self-aligning to the position of the stones on a support surface. 
   Another feature of the present invention is to provide a block impact splitter capable of receiving block supporting production plates having a plurality of precasted concrete blocks and wherein a plurality of block impact splitters are automatically and individually positioned with respect to an associated block for splitting several blocks at the same time. 
   Another feature of the present invention is to provide a block impact splitter utilizing a hammer which is operated by a piston to provide an impact force on a pitching blade which is precisely positioned at a predetermined position with respect to a casted concrete block to be split. 
   Another feature of the present invention is that the blocks are casted, transported and split on their support plate without having to be removed or transferred therefrom. 
   According to the above features, from a broad aspect, the present invention provides a method of producing split casted concrete blocks. The method comprises the steps of providing a production plate adapted to support one or more casted blocks. One or more of these blocks are casted on the production plate. A parting slot is formed on a top surface of each of the one or more blocks. The production plate is transported to a support surface of a block splitting machine. Each of the blocks is impacted with a pitching blade aligned with the parting slot of a respective one of the one or more casted blocks to form the split blocks on the production plate. 

   
     BRIEF DESCRIPTION OF DRAWINGS 
     A preferred embodiment of the present invention will now be described with reference to the accompanying drawings in which: 
       FIG. 1  is a side view showing two block impact splitters, herein a pair of block impact splitters supported in transverse aligned position on a stationary frame; 
       FIG. 2  is a perspective view showing the construction of a block impact splitter constructed in accordance with the present invention; and 
       FIG. 3  is a perspective view showing a stationary frame on which is securable six block impact splitters which are pivotally mounted to the frame in opposed pairs and above a block support plate. 
   

   DESCRIPTION OF PREFERRED EMBODIMENTS 
   Referring now to the drawings and more specifically to  FIGS. 1 and 2 , there is shown generally at  10  a block impact splitter constructed in accordance with the present invention. As illustrated in  FIG. 1 , there are two block impact splitters  10  and  10 ′ secured in transverse alignment with one another on support frames  11  and  11 ′, respectively. A block support surface  12  is disposed at a precise position relative to the frame  11 . The block support surface  12  is herein constituted by a block support production plate  12 ′ which is displaceable under the frame  11  by displaceable support means which, as shown in  FIG. 3 , is provided by a carriage  13  displaceable on tracks  14  disposed under the frame  11 . However, other types of mechanisms can be provided to position the plate under the splitters  10  and  10 ′. An important feature of the present invention is that the blocks are casted on their production plate  12 ′, transported and split without having to be transferred to another support plate. 
   The block impact splitters  10  and  10 ′ comprise a hammer assembly  15  having a hammer head  16  which is secured to a pivotal arm  17  pivotally mounted on a pivot connection  18  to an upright member  11 ′ of the support frame  11 . An actuating piston  19  has a cylinder end  20  pivotally connected to the frame, herein a bracket  21  secured to the upright member  11 ′ by a pivot connection  22 . A piston rod end  23  of the actuating piston  19  is pivotally connected to a bracket  24  secured to the pivotal arm  17  on a pivot connection  25 . 
   The actuating piston  19  displaces the hammer head  16  in a rapid motion to impact against a pitching blade assembly  26  to impact the hammer head  16  on a pitching blade  27  to split a block  28  positioned thereunder. The hammer head  16  is then retracted to its standby position as illustrated in  FIG. 1 . 
   The pitching blade assembly  26  has a pivotal support arm  29  to which is secured the pitching blade  27  at a free end thereof. An impact head  30  constructed from steel is secured to the pivotal support arm above the pitching blade  27  to receive the impact blow from the hammer head  16  and transfer it to the pitching blade  27 . A blade positioner  31  is provided with a blade positioning cylinder  32  which is secured to a rear extension section  29 ′ of the pivotal support arm  29  to position the blade  27  to a standby position as illustrated in  FIG. 1 . The pivotal support arm  29  is pivotally mounted to the upright member  11 ′ by a pivot connection  33 . 
   The blade positioner  31  has a detection means by sensing the displacement of the cylinder rod  34  when an impact force is applied to the impact head  30  causing the pivotal support arm  29  to pivot on the pivot connection  33  pushing against the cylinder  34 . A switch  35  may be provided for this detection and it is connected through its connection  36  to a program logic controller device  37  which senses that the pitching blade has been imparted a pitching force to split the stone  28 . This triggers the retraction cycle of the hammer head  16 . 
   When the hammer head  16  is retracted to its standby position as illustrated in  FIG. 1 , the piston cylinder  32  is actuated whereby to tilt the pitching blade  27  upwardly to clear the space thereunder for receiving another plate  12 ′ with stones to be split. The upstroke of the pivotal support arm  29  is adjustable by a threaded bolt  39  provided under the extension end section  29 ′ of the pivotal support arm  29 . It is pointed out that the piston rod end  34  is not at a fully extended stroke when the pitching blade  27  is positioned at its standby position to permit the piston rod to move slightly within the piston cylinder housing  38  to cushion the blow and to detect the displacement of the pitching blade during the impact stroke to generate a signal. 
   The pitching blade assembly  26  is further provided with a means to adjust the position of the pitching blade  27  relative to the block  28  to be split and more precisely relative to a parting slot  28 ′ provided in the top surface  28 ″ of the block  28 . This means is comprised by a pitching blade aligning arm assembly  40  which is secured to the pivotal support arm  29  for adjusting the lateral position of the pitching blade  27  relative to the block  28 . The pitching blade aligning arm assembly  40  is slidably displaceable along the pivotal support arm  29  at precise increments whereby to handle stones of different sizes and to position the pitching blade  27  at a precise location with respect to the stone sizes. The pitching blade aligning arm assembly  40  is provided with a pivotal hand  41  which is actuable by the piston  42  to position same from a retracted position, as shown by phantom lines  43 , to a vertical working position as herein illustrated in solid line. As hereinshown the support frame  11  is suspended on a swivel support  50  by a bushing  51  secured to an overhead stationary frame member  52 . Accordingly, the support frame  11  can swing on the swivel support  50  and this is necessary to position the splitting blade  27  at a precise location with respect to the position of a block to be split on the support surface  12 . It is pointed out that these support blocks are never disposed at precise locations and for this particular device the tolerance of this position can vary within an inch and a half in distance. When the pivotal hand  41  is lowered to its vertical position, it will engage an edge surface, such as edge  44  of the stone  28  to be split, to position the pitching blade  27  at a precise location relative to the edge of the block engaged by the hand  41  supported on the steel plate  12 . A spring  45  is secured to the frame horizontal beam  52  at  45 ′ and the stationary frame  52  on an upright  52 ″ to compensate for the offset weight of the hammer assembly  15  relative to the upright  1 ′ and particularly to the weight of the hammer head  16 . 
   As shown in  FIG. 1 , the head  16  may be provided with a rear extension pin  46  for receiving weighted discs  47  to adjust the weight of the hammer head and consequently the impact force of the head on the pitching blade. 
   As herein shown, the actuating piston  19  has an air cylinder  55  to displace the piston rod  56  for actuating the hammer head  16 . An air pressure reservoir  60  is connected to a rear chamber  57  of the piston through a hose  58  and a valve  59  which is actuable by the program logic controller  37  to pressurize the rear chamber  57  and to evacuate air therefrom. The air cylinder  55  has a front chamber  62  and the piston rod head  61  is displaced by controlling the air in these chambers  57  and  62 . 
   Accordingly, in order to effect the downstroke of the hammer head  16 , air from the front chamber  62  is evacuated through valve  63  which is operated by the controller  37  and simultaneously air pressure is applied in the rear chamber  57 . This causes the hammer head to be released quickly and impact against the steel disc or impact head  30  to cause the splitter blade  27  to impact against the block and impart a splitting force to split the block exposing a jaggered aggregate face  65  on opposed split faces of the block  28  thereby resulting in two blocks each having a jaggered face resembling real stone. 
   During the retracting stroke of the hammer head  16  the rear chamber is evacuated to atmosphere through the valve  59  and air pressure is applied to the front chamber  62  through valve  63  which is also connected by a line  64  to the pressurized air pressure reservoir  60 . This sequence is initiated by the controller  37 . 
   Accordingly, the program logic controller  37  operates the actuating piston  19  and initiates the downward stroke after receiving signals from the positioner assembly  40  after the controller has received a signal from the switch  35  that the pitching blade has effected a pitching cycle. The program logic controller also receives a signal that the pivotal hand  41  is in engagement with a block to be split. 
   Referring now to  FIG. 3 , it can be seen that these block impact splitters  10  are mounted in an assembly on overhead stationary frame members  52  secured to uprights  70  of a stationary frame. In  FIG. 3  only one block impact splitter  10  is herein shown but these block impact splitters  10  are mounted in pairs on the overhead frame members  52  and suspended therefrom on their swivel connection. The impact splitters  10  have their suspended frame  11  adjustably secured in an adjustment slot  60 . Each block impact splitter of each pair is in transverse alignment. The frame as hereinshown is adapted to support three pairs of these block impact splitters. As hereinshown, there are six concrete casted blocks  28 , each of which is associated with a splitter  10  and each of which is provided with a parting slot  28 ′. Each of the block impact splitters automatically positions its pitching blade at a standby position, as above-described, and over the parting slots of its associated block  28  and once this is detected by the controller all six hammer heads  16  are released simultaneously. The hammer is then retracted as well as the pivotal support arm of the pitching blade and the block support steel plate  12 ′ is carried away on the carriage  13  which is supported on the rails  14  and a further production plate  12 ′ with another six stones are brought into position under the block impact splitters. It is pointed out that these precasted concrete blocks are casted on these steel plates and dried thereon. It is therefore not necessary to manipulate the blocks for the splitting cycle. They remain on their support production plate  12 ′. After splitting, the production plate  12 ′ is conveyed to a block discharge station. Also, most of the dust and particles of the precasted stones remain on the production plate  12 ′ and are evacuated at a remote location. The plate  12 ′ can be a steel, wood or plastic plate. 
   As can be appreciated, this system of splitting blocks is fully automated and only requires personnel to move the production plate and to initiate the controller although most of this work can be done automatically. For example, the production plate  12 ′ could be adapted to trip a switch when it reaches its rest position within the frame  11  under the plate impact splitters  10  thereby initiating the splitting cycle. It can also be discharged automatically with a further support table being advanced within the frame  11  to again initiate the splitters once it reaches its position. As previously described, each of the block impact splitters automatically adjust to the positions of the blocks and is also provided with adjustable means to adapt for splitting blocks of different sizes. Although the stationary frame as hereinshown is provided with six blade splitters, it is also conceivable that the frame can have many more splitters and that only selected ones are programmed to operate depending on the number of blocks that are to be placed on the support production plate  12 ′. 
   It is within the ambit of the present invention to cover any obvious modifications of the preferred embodiment described herein provides such modifications fall within the scope of the appended claims.