Hydraulic press with infinite head rotation

A hydraulic tool for crimping connectors to electrical power lines includes a C-shaped crimping head which is infinitely rotatable with respect to the main body of the hydraulic tool for ease of positioning the tool with respect to workpieces. The invention particularly relates to the means for having a C-shaped head on the tool to achieve universal rotation while maintaining integrity of the hydraulic system across the rotational interface.

BACKGROUND OF THE INVENTION 
The present invention relates to crimping tools particularly to hydraulic 
crimping tools for affixing electrical connectors to wire transmission 
lines. 
Hydraulic tools of this kind have been used for a number of years, as for 
example, Burndy Corporation HYPRESS Models Y35 and Y35-2. These tools 
include hydraulically driven dies for criaping electrical connectors onto 
transmission lines or for splicing transmission lines. 
An hydraulic tool of this kind includes a head member containing the 
crimping dies which can be rotated 180.degree. relative to the operating 
handles for ease of positioning the crimping dies over a workpiece. The 
hydraulic tool is operated by placing the dies in position over an 
electrical connector, rotating a reservoir handle to advance a movable die 
into position on a connector and then pumping the operating handle to 
develop sufficient hydraulic force enabling the dies to crimp the 
connector. Approximately twelve tons of force are developed at the die 
head during a crimping operation. After crimping is complete, the tool is 
disengaged by releasing the hydraulic pressure, and retracting the dies. 
In hydraulic tools of this kind it is desirable to provide for rotation of 
the die head with respect to the operating handles in order to improve 
utility of the tool particularly enabling the operator to position the 
crimping dies over connectors while maintaining a safe and convenient 
posture for operating the tool. A rotatable die head enables the operator 
safely and conveniently to engage and crimp connectors which are difficult 
to reach. 
The Burndy Y35/Y35-2 HYPRESS models have rotatable die heads, however, the 
rotation is limited to 180.degree. relative to the operating handle. 
Rotatable heads for hydraulic press tools are revealed in prior patents of 
which Swanson U.S. Pat. No. 2,821,877 is illustrative. In Swanson the die 
head is fully rotatable with respect to the hydraulic tool handle. The 
upper die is affixed to a C-shaped die head and the lower die is attached 
to a piston ram located within a cylinder formerly in the upper body 
portion of the tool. The die head and the piston ram are interlocking by a 
bolt member so that upper and lower dies are fully rotatable while the 
dies maintain working alignment. The design disclosed in Swanson involves 
rotation of the piston ram within a stationary cylinder and results in 
conflicting design requirements, viz., a fluid tight hydraulic power 
system and ease of rotation of piston ram. Swanson utilizes a set of ball 
bearings for rotating the die head on the stationary upper body of the 
tool. The bearings and their retaining grooves must also withstand the 
full crimping force developed between the die head and the tool during 
crimping operations. Additionally, in rotating the piston ram must prevent 
rotational stress from occurring in an internally mounted ram return 
spring. Swanson does this by means of a ball detent engaging the end of a 
spring retaining bolt. While the ball dent accommodates piston ram 
rotation, it is also called upon to prevent axial movement of the spring 
retaining bolt against the large axially directed clamming force developed 
by the power tool. 
The result is a complex design in Swanson where many parts are called upon 
to serve several conflicting functional requirements. 
SUMMARY OF THE INVENTION 
The present invention is directed to an hydraulic power tool in which the 
die head is infinitely rotatable with respect to operating handles and the 
hydraulic power system so that an operator can position the head for 
engaging a workpiece in a convenient manner. 
According to the present invention, there is provided a new and improved 
hydraulic crimping tool particularly in respect to the mounting 
arrangement by which rotation of the die head is achieved. 
According to the invention, the die head is infinitely rotatable with 
respect to the fixed handle of the pump housing so that the die head may 
be rotated an indeterminate number of revolutions without limit or without 
having to reset or reposition the die head and without stressing die head 
component parts. This arrangement is provided and facilitated by a new and 
useful interconnection between the cylinder and the pump housing and by 
unique fluid flow channels from the pump housing through the pump/die head 
interface. 
OBJECTS OF THE INVENTION 
It is an object of the invention to provide a new and improved hydraulic 
crimping tool with an infinitely rotatable crimping head. 
Another object of the invention is to provide a hydraulic crimping tool 
with an infinitely rotatable head in which the fluid flow from power 
piston to cylinder is conducted axially of the rotatable interface between 
C-shaped head and pump housing. 
Other and further objects of the invention will occur to one upon 
employment of the invention in practice or on an understanding of the 
attached detailed description of the invention. 
DESCRIPTION OF THE DRAWING 
FIG. 1 is an elevational view partly in section, of a hydraulic crimping 
tool according to the present invention. 
FIG. 2 is an enlarged section view of an interface port assembly embodied 
in the tool of FIG. 1. 
FIG. 3 is a perspective view of a retaining collar embodied in the tool of 
FIG. 1.

DETAlLED DESCRIPTION OF PREFERRED EMBODIMENT 
Referring now to the drawing and particularly to FIG. 1, the hydraulic 
crimping tool 10 according to the present invention comprises several 
major components including a rotatable C-shaped die head 12, a pump 
housing 14, and operating handles 16 and 17. 
The die head assembly includes a unitary C shaped head 18, preferably cast 
integral, defining a die cavity 20 between a fixed upper jaw 22 and a 
movable lower jaw 24. The upper jaw is in the form of a cresent and 
receives a U-shaped die 26a supported by spaced ridges 28 and retained by 
a pin 30 and cooperating release shaft 32. The die slips transversely into 
position in the upper jaw crescent. The lower jaw 24 is also in the form 
of a crescent at the upper surface of a piston ram 34 receiving a lower U 
shaped die 26b (preferably identical to the upper die) between spaced 
supporting ridges 36 and being retained by a lock pin 38. As more fully 
described below, the upper and lower dies engage a connector workpiece 
(not shown) crimping it into place with substantial crimping force 
developed by operating the tool. 
The die head 18 includes an integral tubular hub 40 for receiving a 
cylinder and piston subassembly 42. The cylinder 44 opens upwardly toward 
the die cavity for receiving the piston ram 34 in telescoping relation. 
The cylinder body 44 is threaded at 48 along its upper surface above a 
circumferential ridge 50 for assembly and retention within tubular hub 40. 
A suitable fastener 52 secures die head 18 and cylinder body 44 against 
relative rotation when assembled. 
The piston ram 34 is slidably received within the cylinder bore 54 and is 
recessed at 56 along its skirt 58 to receive piston rings 60. A piston 
washer 62 and a wiper 64 are positioned at the cylinder open end. A 
longitudinal groove 66 extends along the side of piston head for 
engagement with a guiding key 68 attached to the die head 18 so that the 
piston maintains axial alignment as it emerges from the cylinder during 
operation. 
The under side of the piston ram 34 is downwardly open defining an interior 
cavity 70 for receiving a ram retracting coil spring 72. An axial 
retaining pin 74 is fastened to the under side of the piston head 76 and 
receives an upper spring retaining collar 78. The collar is threaded onto 
the retaining pin and the upper end of the coil spring is threaded onto a 
corresponding spiral groove 80 in the side face of the collar. The lower 
end of the coil spring is similarly retained in spiral groove 81 of lower 
collar 82 affixed to the cylinder base 84. The lower collar includes a 
port 85 for admitting hydraulic fluid to the piston interior. In 
operation, the coil spring 72 expands as the piston ram advances from the 
cylinder into the die cavity and retracts the ram when operating hydraulic 
pressure is released. 
The base of the cylinder body includes a central orifice 86 accommodating 
an interface port 88 (FIG. 2) and a bottom interface surface 90 necked 
below a circumferential shoulder 92 for engagement with the pump housing 
14. The cylinder interface surface 90 and the complementary pump housing 
upper surface 94 define a rotational interface 95 between die head 
assembly and remainder of the hydraulic tool. The cylinder base and the 
pump housing contain confronting coplanar grooves 96a and 96b on opposite 
sides of the rotational interface 95 (FIG. 4m for receiving a retaining or 
locking collar 98 held in place by means of a set screw 100. The grooves 
extend the entire circumference of cylinder base and pump housing. The 
retaining collar and grooves preferably have rectangular cross-sections. 
The collar 98 is fabricated of robust spring steel of sufficient 
mechanical strength to retain the die head and piston/cylinder subassembly 
in fixed axial position with respect to the pump housing without deforming 
under the substantial hydraulic operating force developed as the dies are 
crimping a connector workpiece. Additionally, the retaining collar 
interconnects cylinder base and pump housing allowing infinite rotation 
clockwise and counter-clockwise of die head on the hydraulic tool at the 
die head/pump housing interface 95: The collar occupies confronting groves 
96a, 96b through substantially their entire circumference. One end of the 
collar includes a loop 97 for gripping the collar as it is inserted into 
the grooves during tool assembly through an opening 99 in the pump 
housing. Set screw 100 holds the collar in position in final assembly of 
the tool. In order to remove the die head from the tool for maintenance, 
inspection, and so forth, set screw is removed and the collar is removed 
from its grooves through access opening. The die head subassembly can now 
be removed from the tool. 
The interface port assembly 88 is illustrated in FIGS. 1 and 3. The 
interface port establishes a fluid tight passage for hydraulic power fluid 
across the rotational interface 95. The interface port is fitted into 
aligned orifices 102, 104 in the cylinder base and in the pump housing 
defining a fluid channel between hydraulic power pump and the under side 
of piston ram. The interface port lies along the longitudinal axis X'--X" 
of the tool which is the axis of rotation of die head with respect to the 
reservoir handle 16. The interface port communicates the power pump outlet 
to the piston ram across the rotational interface without admitting 
pressurized fluid to the interface. The interface port includes a tubular 
port body 106 with an internal duct 108 defining a flow channel for 
hydraulic fluid from pump housing to the piston ram. The flow channel is 
provided with a ball-check valve 110 including a spring llZ urging valve 
ball 114 against a valve seat 116 formed in the side wall of the channel. 
A retaining ring 118 holds the spring in position at the outlet end 120 of 
the port body. The interface port is fitted into a recess in the pump 
housing with ports 122 aligned with a channel 124 (FIG. 1). A retaining 
ring 126 secures the interface port against axial movement across the 
interface. The outer surface of the interface port is provided three sets 
of 0-rings 128 and back-up rings 130 to assure fluid tightness of the 
interface port. With this axial alignment of the interface port, the die 
head can be rotated to any desired position while fluid communication from 
power pump to piston ram remains unaffected. 
The power housing 14 also includes an hydraulic pump 132, a pressure relief 
valve 134, and suitable internal ducting 136 for directing hydraulic fluid 
during operation of the tool. 
The pump includes a cylinder 138 and large 140 and small 142 pistons 
connected to a piston rod 144 reciprocated by operating handle 146 
pivotally attached to the main body by suitable connecting arms 148 and 
pivot shaft 150. The outer piston when operated pressurizes the hydraulic 
fluid in the reservoir handle 152 through pump housing ducts (not shown) 
interconnecting pressure chamber 154, the reservoir 156, and the main 
cylinder head 86. The pressure so developed by large piston 140 primes the 
main cylinder head with low pressure hydraulic fluid to advance the piston 
ram and lower die into engagement with the connector workpiece against the 
force of retracting spring 72. Continued reciprocation of the operating 
handle develops the high operational hydraulic fluid crimping pressure by 
means of small piston 142. The pressure so developed urges the dies with 
full force completing the crimping operation. 
The interface port 122 bleeds high pressure hydraulic fluid through relief 
channels 124, 136 and 137 to a pressure relief valve 134. The pressure 
relief valve 134 releases pressurized fluid through internal pump housing 
channels (not shown) to reservoir 156 when full operating pressure is 
achieved Expansion spring 72 will then retract the lower die from a 
connector workpiece. 
In operation, the hydraulic press die head is rotated manually to a 
convenient position for the operator to engage a connector workpiece. By 
reciprocating the operating handle, the piston ram advances moving the 
dies into engagement with a connector workpiece. The operator actuates the 
power pump by continuing the reciprocation of the pump handle thereby 
delivering pressurized hydraulic fluid from the pump through the interface 
port to the piston ram. As fluid pressure develops the dies crimp the 
workpiece connector into place. Thereafter, the fluid pressure is relieved 
by the pressure relief valve either hydraulically or mechanically 
returning pressurized fluid through relief valve ducts into the reservoir. 
It will be thus seen that the present invention represents a substantial 
improvement in the utility of hydraulic crimping tools with infinitely 
rotatable die heads.