CN113027721A

CN113027721A - Base body assembly for short-body electro-hydraulic tool

Info

Publication number: CN113027721A
Application number: CN202110160078.XA
Authority: CN
Inventors: 王俊; 彭亚民; 董建华
Original assignee: European Shield Technology Co ltd
Current assignee: European Shield Technology Co ltd
Priority date: 2020-12-03
Filing date: 2021-02-05
Publication date: 2021-06-25

Abstract

The invention provides a base body assembly for a short-body electro-hydraulic tool, which comprises an oil cylinder and an assembly body. The assembly body is connected to the oil inlet end of the oil cylinder along the axial direction of the oil cylinder, and a motor mounting hole and a pump body assembly surface are formed in the assembly body; the axis of the motor mounting hole is intersected with the axis of the oil cylinder so that the motor assembly of the assembled electric hydraulic tool extends along one side of the oil cylinder. The pump body assembly surface matched and connected with the pump body assembly of the electric hydraulic tool is formed at the end part of the motor mounting hole so that the motor assembly penetrates through the motor mounting hole to be connected with the pump body assembly, and the pump body assembly surface is provided with a plurality of oil inlet holes and at least one oil return hole which are communicated with the oil cylinder.

Description

Base body assembly for short-body electro-hydraulic tool

Technical Field

The present invention relates to an electrohydraulic tool accessory, and more particularly to a base assembly for a short body electrohydraulic tool.

Background

The electric hydraulic tool is a tool for converting the rotary mechanical energy of power machinery (such as an internal combustion engine and an electric motor) into hydraulic energy and outputting the hydraulic energy, and is widely used for concrete engineering construction, demolition construction or important tools for emergency rescue and disaster relief. The traditional electric hydraulic device is mostly split type, and comprises a hydraulic main body and a working head which are large and heavy, so that the device is inconvenient to carry and is difficult to operate in a space with a small size, and particularly, the device is used in occasions of emergency rescue and disaster relief.

To solve this problem, integral hand-held electro-hydraulic tools are currently on the market. Compared with the traditional split type electro-hydraulic device, the integrated handheld electro-hydraulic tool is greatly improved in size and weight. However, the existing integrated handheld electric hydraulic tool is mostly designed in a linear type with a long machine body, the whole length of the whole tool is very long, the occupied space is large, and the operation is very inconvenient due to the fact that the length exceeds the optimal distance of human mechanics.

Disclosure of Invention

The invention provides a base body assembly for a short-body electro-hydraulic tool, which can shorten the body of the electro-hydraulic tool, and aims to overcome the problems of long body and large volume of the existing integrated handheld electro-hydraulic tool.

In order to achieve the above object, the present invention provides a base assembly for a short-body electrohydraulic tool, which includes a cylinder and an assembling body. The assembly body is connected to the oil inlet end of the oil cylinder along the axial direction of the oil cylinder, and a motor mounting hole and a pump body assembly surface are formed in the assembly body; the axis of the motor mounting hole is intersected with the axis of the oil cylinder so that the motor assembly of the assembled electric hydraulic tool extends along one side of the oil cylinder. The pump body assembly surface matched and connected with the pump body assembly of the electric hydraulic tool is formed at the end part of the motor mounting hole so that the motor assembly penetrates through the motor mounting hole to be connected with the pump body assembly, and the pump body assembly surface is provided with a plurality of oil inlet holes and at least one oil return hole which are communicated with the oil cylinder.

According to one embodiment of the invention, the motor mounting hole extends from one end of the assembly body where the pump body assembly surface is located to the other end along a direction parallel to the radial direction of the oil cylinder, the axis of the motor mounting hole is perpendicular to the axis of the oil cylinder, and the assembled motor assembly extends along the direction perpendicular to the axis of the oil cylinder.

According to an embodiment of the present invention, the assembly body further has a plurality of pump body limiting portions protruding from the pump body assembly surface and distributed along a circumferential direction of the pump body assembly surface, and the plurality of pump body limiting portions are respectively disposed corresponding to the plurality of plungers in the pump body assembly connected to the pump body assembly surface.

According to an embodiment of the invention, the cross section of each pump body limiting part is gradually reduced from the connecting end connected with the pump body assembling surface to the free end, and the limiting surface of each pump body limiting part close to the center of the assembling body is a plane.

According to an embodiment of the present invention, the mounting body further has a tank connecting portion formed on an outer periphery of the pump body mounting surface.

According to an embodiment of the present invention, each of the oil inlet holes includes a first oil inlet section extending along a longitudinal section of the assembly body where the oil inlet hole is located and a second oil inlet section parallel to an axis of the cylinder, the second oil inlet section communicating with the rodless cavity of the cylinder.

According to an embodiment of the present invention, the base assembly further includes an automatic pressure relief oil path therein, the automatic pressure relief oil path includes a first oil return path and a second oil return path that are communicated with each other, the first oil return path is communicated with the rod cavity of the oil cylinder and extends along the sidewall of the oil cylinder, and the second oil return path extends along the assembly body and is communicated with the at least one oil return hole.

According to an embodiment of the invention, a triggered pressure relief oil path is arranged in the assembly body, one end of the triggered pressure relief oil path is communicated with the rodless cavity of the oil cylinder, the other end of the triggered pressure relief oil path is communicated with at least one oil return hole of the assembly surface of the pump body, a pressure relief valve mounting hole for mounting a pressure relief valve is formed in the side wall of the assembly body, the inner end of the pressure relief valve mounting hole is communicated with the triggered pressure relief oil path, and the pressure relief valve opens or blocks the triggered pressure relief oil path.

According to an embodiment of the present invention, when the assembly body has the automatic pressure relief oil path and the triggered pressure relief oil path, the assembly surface of the pump body has two oil return holes, a first oil return hole is communicated with the automatic pressure relief oil path, and a second oil return hole is communicated with the triggered pressure relief oil path.

According to one embodiment of the invention, the side wall of the oil cylinder is provided with an annular groove for rotatably connecting with the handheld part of the electric hydraulic tool, and the front end of the oil cylinder is provided with a thread for detachably connecting with the working head component of the hydraulic tool.

In summary, the base assembly for the short-body electro-hydraulic tool provided by the invention has the motor mounting hole on the assembly body, wherein the axis of the motor mounting hole intersects with the axis of the oil cylinder, the motor mounting hole is arranged so that the assembled motor assembly extends along one side of the base assembly, and the extending direction of the motor assembly intersects with the axial direction of the oil cylinder. The device greatly shortens the axial length of the electric hydraulic tool in the oil cylinder, and greatly facilitates the operation of a user. The pump body assembly surface on the assembly body provides a space for the assembly of the pump body assembly, and the arrangement of the plurality of oil inlets and the at least one oil return hole on the pump body assembly surface not only realizes the transmission of oil from the radial direction of the oil cylinder to the axial direction of the oil cylinder, but also greatly simplifies the oil circuit design of the oil tank, the pump body assembly and the oil cylinder.

In order to make the aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below.

Drawings

Fig. 1 is a schematic structural view of a base unit for a short-body electrohydraulic tool according to an embodiment of the present invention.

Fig. 2 to 5 are schematic structural views of fig. 1 from another view angle.

Figure 6 shows a cross-sectional view of figure 2 along line a-a.

Fig. 7 is a cross-sectional view taken along line B-B of fig. 6.

Fig. 8 is a cross-sectional view taken along line C-C of fig. 2.

Fig. 9 is a cross-sectional view taken along line D-D of fig. 3.

Fig. 10 is a cross-sectional view taken along line E-E of fig. 5.

Fig. 11 is a cross-sectional view taken along line F-F of fig. 10.

FIG. 12 is a schematic view of a short body electrohydraulic cutter.

Fig. 13 is a cross-sectional view of fig. 12.

Fig. 14 is an exploded view of fig. 12.

Fig. 15 is a partial schematic view of fig. 14.

Detailed Description

As shown in fig. 1 to 11, the base assembly 10 for a short-body electro-hydraulic tool provided in the present embodiment includes a cylinder 1 and a fitting body 2. The assembly body 2 is connected to the oil inlet end of the oil cylinder 1 along the axial direction of the oil cylinder 1, and the assembly body 2 is provided with a motor mounting hole 21 and a pump body assembly surface 22; the axis of the motor mounting hole 21 intersects the axis of the cylinder 1 so that the motor assembly of the assembled electro-hydraulic tool extends along one side of the cylinder 1. The pump body assembly surface 22 matched and connected with the pump body assembly of the electric hydraulic tool is formed at the end part of the motor mounting hole 21 so that the motor assembly penetrates through the motor mounting hole 21 to be connected with the pump body assembly, and the pump body assembly surface 22 is provided with a plurality of oil inlet holes 221 and at least one oil return hole which are communicated with the oil cylinder.

The axis of the motor mounting hole 21 in the base body assembly 10 for the short-body electro-hydraulic tool provided by the embodiment intersects with the axis of the oil cylinder 1, and the arrangement enables the motor assembly of the electro-hydraulic tool to extend along the side edge of the base body assembly, so that the size of the whole hydraulic tool in the axial direction of the oil cylinder 1 is shortened, and the large-amplitude shortening of the body is realized. In the present embodiment, the axis of the motor mounting hole 21 is perpendicular to the axis of the cylinder 1. However, the present invention is not limited thereto. In other embodiments, the angle formed by the intersection between the axis of the motor mounting hole and the axis of the cylinder may be other angles less than 90 degrees.

In the present embodiment, as shown in fig. 12 to 14, when the base assembly 10 for a short-body electro-hydraulic tool is assembled with the four-plunger pump body assembly 20, the plunger carrier 201 has a through hole 2011 in the middle thereof, and the plunger carrier 201 has four plunger mounting holes 2012 uniformly distributed along the circumferential side wall thereof and four sets of pump oil holes (not shown) formed in the end surface of the plunger carrier 201 and communicated with the four plunger mounting holes 2012 (for the reason of view angle). The four plungers 202 are respectively disposed in the four plunger mounting holes 2012. An eccentric shaft 401 of the motor assembly 40 penetrates through the motor mounting hole 21 from bottom to top and extends into the through hole 2011, the eccentric shaft 401 drives a needle bearing 402 connected with the eccentric shaft to rotate, the peripheral wall of the needle bearing 402 continuously extrudes the four plungers 202, and therefore oil is pumped out of the four groups of pump oil holes, and each group of pump oil holes comprises two pump oil holes. However, the present invention is not limited thereto.

The pump body mounting surface 22 has four oil inlets 221 opposite to the four sets of pumping holes, and the upper end of each oil inlet 221 has an oval oil collecting groove 223. During assembly, the oil outlet end face of the plunger carrier 201 abuts against the pump body assembly face 22 and the two are fixedly connected through eight screws. After the assembly is completed, four groups of pump oil holes on the plunger carrier 201 are respectively butted with the four oil collecting grooves 223, and oil output by each group of pump oil holes is collected by the oil collecting grooves 223 and then enters the oil inlet 221. The oil collecting groove 223 is arranged to realize the conversion from the double-pump oil hole on the pump body assembly 20 to the single oil inlet hole 221 on the assembly body 2, so that the existing plunger pump is well matched and compatible, only four oil inlet holes need to be formed on the assembly body 2, and the processing of the assembly body 2 is greatly simplified. However, the present invention is not limited thereto. In other embodiments, eight (four) oil inlets may be formed in the mounting body, and each oil inlet is independently butted with one pumping hole. Or, in other embodiments, when the pump body assembly is two plungers, three plungers, five plungers or other number of plungers, the assembly body is provided with oil inlet holes matched with the number of the plungers.

In the present embodiment, as shown in fig. 1 and fig. 2, the assembly body 2 further has four pump body limiting parts 23, the four pump body limiting parts 23 protrude from the pump body assembly surface 22 and are distributed along the circumferential direction of the pump body assembly surface 22, and the four pump body limiting parts 23 are respectively disposed corresponding to the four plungers 202. The four pump body stoppers 23 block and limit outer end portions of the four plungers 202 mounted in the plunger mounting holes 2012 in the pump body assembly 20. Meanwhile, the four pump body limiting parts 23 are arranged to realize positioning of the pump body assembly 20 and the pump body assembly surface 22 during assembly, so that the oil inlet hole in the pump body assembly surface 22 is accurately matched with the pump oil hole in the plunger carrier after assembly, oil pumped out from the pump oil hole completely enters the oil inlet hole without leakage, and the use safety of the hydraulic tool is greatly improved. However, the present invention is not limited thereto. In other embodiments, the number and location of the pump body stops will vary adaptively depending on the number and location of the plungers within the pump body assembly. Preferably, the concentration of the organic acid in the organic acid solution,

in this embodiment, the cross section of each pump body limiting portion 23 gradually decreases from the connecting end connected with the pump body assembling surface 22 to the free end, and the limiting surface of each pump body limiting portion near the center of the assembling body is a flat surface. The connecting end with the large cross section area ensures the connecting strength between the pump body limiting part 23 and the pump body assembling surface 22, and stably blocks the plunger which reciprocates at high speed so as to ensure stable oil outlet. The free end of smaller cross-sectional area provides more space for the tank to be attached to the pump body mounting surface 22 and to be wrapped around the outside of the pump body assembly. However, the present invention is not limited thereto.

In the present embodiment, as shown in fig. 1 and 2, the mount body 2 further includes a tank connection portion 24 formed on the outer periphery of the pump body mount surface 22. In fig. 12, the oil tank 30 is provided in the tank connection portion 24 and covers the pump body assembly 20. However, the present invention is not limited thereto. In other embodiments, the fuel tank may be mounted to a side wall of the mounting body.

Describing the positional relationship of each component in the base assembly for the short-body electro-hydraulic tool in fig. 3, since the pump body assembly is disposed above the assembly body 2, the pump oil hole pumps the oil from top to bottom in the vertical direction into the oil sump 223; and the oil inlet direction of the oil cylinder 2 is a horizontal axial direction. Therefore, the oil inlet hole 221 needs to convert oil transferred in the vertical direction into oil transferred in the cylinder axial direction. In this embodiment, as shown in fig. 6 and 7, each oil inlet 221 is provided with a first oil inlet 2211 extending along the longitudinal section of the assembly body where the oil inlet 221 is located and a second oil inlet 2212 parallel to the axis of the cylinder, and the oil enters the oil collecting groove 223, then enters the first oil inlet 2211 along the longitudinal direction of the assembly body 2, and then is delivered into the rodless cavity 101 of the cylinder through the second oil inlet 2212. Because the middle part of assembly body 2 has motor mounting hole 21, in order to avoid when processing because the interval between first oil feed section 2211 and the motor mounting hole 21 is too little and arouse the processing interference, set up first oil feed section 2211 and expand outward gradually and be the slope form when along assembly body 2 longitudinal extension to increase the process space between its and the motor mounting hole 21. However, the present invention is not limited thereto. In other two implementations, when the width of the assembly body is sufficient, the first oil inlet section may be a straight hole with an axis parallel to the axis of the motor installation hole.

In this embodiment, the base assembly 1 has an automatic pressure relief oil path 4 and a trigger pressure relief oil path 5 therein, and correspondingly, the assembly body 2 has two oil return holes, which are a second oil return hole 223 communicating with the automatic pressure relief oil path 4 and a first oil return hole 222 communicating with the trigger pressure relief oil path 5. However, the present invention is not limited thereto. In other embodiments, the assembly body has only one oil return hole, and the automatic pressure relief oil path and the triggered pressure relief oil path are both communicated with the oil return hole.

In this embodiment, one end of the automatic pressure relief oil path 4 is connected to the rod chamber 102 of the cylinder through the sidewall of the cylinder 1, and the other end extends to the second oil return hole 223 along the cross section of the second oil return hole 223 on the assembly body 2. Specifically, as shown in fig. 6 and 7, the automatic pressure relief oil path 4 includes a first oil return path 41 and a second oil return path 42 that are communicated with each other, the first oil return path 41 is communicated with the rod cavity 102 of the cylinder through the cylinder oil outlet hole 11 on the cylinder and extends along the side wall of the cylinder 1, and the second oil return path 42 extends along the assembly body 2 and is communicated with the second oil return hole 223. As shown in fig. 6, the second oil gallery 42 extends along a longitudinal section of the fitting body 2; similarly, in order to avoid interference between the second oil return channel 42 and the motor mounting hole 21 during machining, the second oil return channel 42 is arranged on the longitudinal section of the assembly body and gradually expands outwards from the pump body assembly 20 to the motor assembly 40 so as to increase the machining distance between the second oil return channel and the motor mounting hole 21, and the machining difficulty is simplified. However, the present invention is not limited thereto.

Further, as shown in fig. 8 to 11, a trigger type pressure relief oil path 5 is provided in the assembly body 2, one end of the trigger type pressure relief oil path 5 is communicated with the rodless cavity 101 of the oil cylinder, the other end of the trigger type pressure relief oil path is communicated with the first oil return hole 222 of the pump body assembly surface, a pressure relief valve mounting hole 25 for mounting a pressure relief valve is provided on the side wall of the assembly body 2, and the inner end of the pressure relief valve mounting hole 25 is communicated with the trigger type pressure relief oil path 5. Specifically, the trigger type relief oil passage 5 includes an axial straight section 51, a vertical section 52, and an inclined section 53. The axial straight section 51 is communicated with the oil cylinder rodless cavity 101 and is arranged along the axial direction of the oil cylinder; the vertical section 52 is respectively communicated with the axial straight section 51 and the relief valve mounting hole 25; one end of the inclined section 53 is communicated with the relief valve mounting hole 25, and the other end is communicated with the first oil return hole 222. The relief valve provided in the relief valve installation hole 25 communicates or blocks the vertical section 52 and the inclined section 53. However, the present invention is not limited thereto. In other embodiments, the relief valve mounting hole may also be directly connected to the rodless cavity of the cylinder via an inclined oil passage.

Fig. 12 to 15 show a short-body electrohydraulic cutting machine of the base unit 10 for a short-body electrohydraulic tool. The pump body assembly 20 is fixedly connected to the pump body matching surface 22 through eight screws, the oil tank 30 is connected to an oil tank connecting portion 23 located outside the pump body matching surface 22, and the oil tank 30 covers the pump body assembly 20. The motor assembly 40 penetrates through the shooting motor mounting hole 21 and extends into the pump body assembly 20 to drive the four plungers to reciprocate. The piston shaft assembly 50 is disposed within the cylinder 1 to divide the cylinder into a rodless chamber 101 and a rod chamber 102. The frame 601 in the working head assembly 60 is provided with an external thread matched with the internal thread 13 at the end part of the oil cylinder 1, and the frame 601 extends into the oil cylinder 1 and is connected with the oil cylinder 1 in a threaded manner. However, the present invention is not limited thereto. In other embodiments, the base assembly for a short-body electro-hydraulic tool provided by the invention can be connected with any working head assembly of a punching machine, a shearing machine, a bending machine or a riveting machine to form a corresponding electro-hydraulic tool.

The operation principle of the base assembly for a short-body electro-hydraulic tool according to the present embodiment applied to the electro-hydraulic tool will be described below with reference to fig. 1 to 15.

In the oil-in state, the motor assembly 40 drives the plurality of plungers 202 in the pump body assembly 20 to reciprocate, and the plungers 202 reciprocate while pumping the oil in the oil tank 30 out of the pump oil holes. Oil enters the rodless cavity 101 of the oil cylinder through the first oil inlet section 2211 and the second oil inlet section 2212, the oil pressure in the rodless cavity 101 is increased, the piston shaft assembly 50 is pushed to move forwards, and the moving cutter head 602 moves forwards along with the push shaft 501 in the piston shaft assembly and processes materials on the frame 601. As shown in fig. 13, when the small piston 502 on the piston shaft assembly 50 abuts against the end K of the frame 601 extending into the oil cylinder 1, the small piston 502 retreats and opens the small piston mounting hole at the bottom of the push shaft, the rod chamber 102 and the rodless chamber 101 in the oil cylinder 1 are communicated, and the oil in the rodless chamber 101 enters the rod chamber 102 and enters the second oil return hole 223 through the first oil return channel 41 and the second oil return channel 42 in the automatic pressure relief oil path 4, and then enters the oil tank 30 for oil return. The oil pressure in the rodless chamber 101 decreases, and the push shaft 501 retreats and returns under the action of the push shaft spring.

When the oil pressure in the oil cylinder 1 is too high or the electric hydraulic tool fails, a user can manually open the pressure relief valve 6, the vertical section 52 and the inclined section 53 in the triggered pressure relief oil path 5 are communicated, and the oil in the rodless cavity 101 of the oil cylinder enters the first oil return hole 222 through the axial straight section 51, the vertical section 52 and the inclined section 53 and then enters the oil tank.

In the embodiment, the side wall of the cylinder 1 has an annular groove 12 for rotatably connecting a handle portion 70 of the electro-hydraulic tool, and the handle portion 70 is rotatably sleeved in the annular groove 12 and can rotate 360 degrees around the cylinder. When the machine is placed on the ground for work, the user can rotate the hand-held part 70 to a proper angle so that the frame 601, the hand-held part 70 and the motor assembly 40 are distributed triangularly to support the short-body type electro-hydraulic tool, the operation is very stable, the operation view is wide, and the work is convenient.

Although the present invention has been described with reference to the preferred embodiments, it should be understood that various changes and modifications can be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

1. A base body assembly for a short-body electro-hydraulic tool is characterized by comprising an oil cylinder and an assembly body; the assembling body is connected to the oil inlet end of the oil cylinder along the axial direction of the oil cylinder, and a motor mounting hole and a pump body assembling surface are formed in the assembling body; the axis of the motor mounting hole is intersected with the axis of the oil cylinder so that a motor assembly of the assembled electric hydraulic tool extends along one side of the oil cylinder;

the pump body assembly surface matched and connected with the pump body assembly of the electric hydraulic tool is formed at the end part of the motor mounting hole so that the motor assembly penetrates through the motor mounting hole to be connected with the pump body assembly, and the pump body assembly surface is provided with a plurality of oil inlet holes and at least one oil return hole which are communicated with the oil cylinder.

2. The base unit assembly for a short body electrohydraulic tool according to claim 1, wherein the motor mounting hole extends from one end of the mounting body where the pump body mounting surface is located to the other end in a direction parallel to a radial direction of the cylinder, an axis of the motor mounting hole is perpendicular to an axis of the cylinder, and the motor assembly extends in a direction perpendicular to the axis of the cylinder after the mounting.

3. The base body assembly for a short body electrohydraulic tool according to claim 1 further including a plurality of pump body limiting portions formed on the mounting body, the plurality of pump body limiting portions projecting from the pump body mounting surface and being arranged along a circumferential direction of the pump body mounting surface, the plurality of pump body limiting portions being respectively disposed to correspond to the plurality of plungers mounted in the pump body assembly on the pump body mounting surface.

4. The base body assembly for the short body electrohydraulic tool according to claim 3, wherein a cross section of each of the pump body retainer portions is gradually reduced from a connecting end connected to the pump body fitting surface to a free end and a retainer surface of each of the pump body retainer portions near a center of the fitting body is a flat surface.

5. The base unit for the short body electrohydraulic tool according to claim 1, further comprising a tank connecting portion formed on an outer periphery of the pump body mounting surface on the mounting body.

6. The base assembly for a short body electrohydraulic tool of claim 1 wherein each of the oil feed holes includes a first oil feed portion extending along a longitudinal section of the assembly body where the oil feed hole is located and a second oil feed portion parallel to the axis of the cylinder, the second oil feed portion communicating with the rodless chamber of the cylinder.

7. The base assembly for a short body electrohydraulic tool of claim 1 further including an automatic pressure relief circuit disposed within the base assembly, the automatic pressure relief circuit including a first oil return passage and a second oil return passage in communication with each other, the first oil return passage communicating with the rod cavity of the cylinder and extending along the sidewall of the cylinder, the second oil return passage extending along the mounting body and communicating with the at least one oil return hole.

8. The base body assembly for the short-body electro-hydraulic tool according to claim 1 or 6, characterized in that a trigger type pressure relief oil path is arranged in the assembly body, one end of the trigger type pressure relief oil path is communicated with a rodless cavity of the oil cylinder, the other end of the trigger type pressure relief oil path is communicated with at least one oil return hole of the assembly surface of the pump body, a pressure relief valve mounting hole used for mounting a pressure relief valve is arranged on the side wall of the assembly body, the inner end of the pressure relief valve mounting hole is communicated with the trigger type pressure relief oil path, and the pressure relief valve opens or.

9. The base unit assembly for a short body electrohydraulic tool according to claim 8, wherein when the automatic relief oil passage and the trigger type relief oil passage are provided in the fitting body, two oil return holes are provided in the fitting surface of the pump body, the first oil return hole communicates with the automatic relief oil passage, and the second oil return hole communicates with the trigger type relief oil passage.

10. The base unit for a short body electrohydraulic tool of claim 1 wherein the side wall of the cylinder has an annular recess for rotatably connecting to a hand-held portion of the electrohydraulic tool and the front end of the cylinder has threads for removably connecting to a head unit of the hydraulic tool.